# Source: https://docs.datadoghq.com/security/code_security/iac_security/iac_rules/terraform/azure/vm_not_attached_to_network.md

---
title: VM not attached to network
description: Datadog, the leading service for cloud-scale monitoring.
breadcrumbs: >-
  Docs > Datadog Security > Code Security > Infrastructure as Code (IaC)
  Security > IaC Security Rules > VM not attached to network
---

# VM not attached to network

{% callout %}
# Important note for users on the following Datadog sites: app.ddog-gov.com

{% alert level="danger" %}
This product is not supported for your selected [Datadog site](https://docs.datadoghq.com/getting_started/site). ().
{% /alert %}

{% /callout %}

## Metadata{% #metadata %}

**Id:** `bbf6b3df-4b65-4f87-82cc-da9f30f8c033`

**Cloud Provider:** Azure

**Platform:** Terraform

**Severity:** Medium

**Category:** Insecure Configurations

#### Learn More{% #learn-more %}

- [Provider Reference](https://registry.terraform.io/providers/hashicorp/azurerm/latest/docs/resources/virtual_machine#network_interface_ids)

### Description{% #description %}

Attaching a Network Security Group (NSG) to a virtual machine in Azure is essential for defining and restricting inbound and outbound traffic. Without an NSG, as in the configuration below where `network_interface_ids` is set to an empty list and no NSG is associated, the virtual machine is left exposed to unrestricted network access, increasing the risk of unauthorized access and potential security breaches.

```
resource "azurerm_virtual_machine" "example" {
  name                  = "example-vm"
  location              = azurerm_resource_group.example.location
  resource_group_name   = azurerm_resource_group.example.name
  network_interface_ids = []
  vm_size               = "Standard_DS1_v2"
}
```

To mitigate this risk, ensure NSGs are attached by associating them with the network interface connected to the VM, as shown below:

```
resource "azurerm_network_interface" "example" {
  name                = "example-nic"
  location            = azurerm_resource_group.example.location
  resource_group_name = azurerm_resource_group.example.name

  ip_configuration {
    name                          = "internal"
    subnet_id                     = azurerm_subnet.example.id
    private_ip_address_allocation = "Dynamic"
  }
}

resource "azurerm_network_interface_security_group_association" "example" {
  network_interface_id      = azurerm_network_interface.example.id
  network_security_group_id = azurerm_network_security_group.example.id
}
```

Neglecting to configure and attach an NSG can result in unrestricted network exposure for the VM, leading to increased vulnerability to attacks, unauthorized access, and data breaches.

## Compliant Code Examples{% #compliant-code-examples %}

```terraform
resource "azurerm_network_interface" "negative1" {
  name                = "${var.prefix}-nic"
  location            = azurerm_resource_group.main.location
  resource_group_name = azurerm_resource_group.main.name

  ip_configuration {
    name                          = "testconfiguration1"
    subnet_id                     = azurerm_subnet.internal.id
    private_ip_address_allocation = "Dynamic"
  }
}

resource "azurerm_virtual_machine" "negative2" {
  name                  = "${var.prefix}-vm"
  location              = azurerm_resource_group.main.location
  resource_group_name   = azurerm_resource_group.main.name
  network_interface_ids = [azurerm_network_interface.main.id]
  vm_size               = "Standard_DS1_v2"

  os_profile_linux_config {
    disable_password_authentication = false
  }
}
```

## Non-Compliant Code Examples{% #non-compliant-code-examples %}

```terraform
resource "azurerm_virtual_machine" "positive1" {
  name                  = "${var.prefix}-vm"
  location              = azurerm_resource_group.main.location
  resource_group_name   = azurerm_resource_group.main.name
  network_interface_ids = []
  vm_size               = "Standard_DS1_v2"

  os_profile_linux_config {
    disable_password_authentication = false
  }
}
```