---
title: CVM instance using default security group
description: Datadog, the leading service for cloud-scale monitoring.
breadcrumbs: >-
  Docs > Datadog Security > Code Security > Infrastructure as Code (IaC)
  Security > IaC Security Rules > CVM instance using default security group
---

> For the complete documentation index, see [llms.txt](https://docs.datadoghq.com/llms.txt).

# CVM instance using default security group

{% callout %}
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{% alert level="danger" %}
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{% /callout %}

## Metadata{% #metadata %}

**Id:** `terraform-tencentcloud-cvm-instance-using-default-security-group` 

**Provider:** TencentCloud

**Platform:** Terraform

**Severity:** Low

**Category:** Access Control

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

- [Provider Reference](https://registry.terraform.io/providers/tencentcloudstack/tencentcloud/latest/docs/resources/instance#orderly_security_groups)

### Description{% #description %}

CVM instances (`tencentcloud_instance`) should explicitly specify a security group. When neither `orderly_security_groups` nor `security_groups` is set, TencentCloud automatically attaches the account's default security group, which allows all IPv4 traffic. Relying on the default security group can result in overly permissive network access and should be avoided.

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

```terraform
resource "tencentcloud_instance" "cvm_postpaid" {
  instance_name     = "cvm_postpaid"
  availability_zone = "ap-guangzhou-7"
  image_id          = "img-9qrfy1xt"
  instance_type     = "S1.SMALL1"
  system_disk_type  = "CLOUD_PREMIUM"
  system_disk_size  = 50
  hostname          = "root"
  project_id        = 0
  vpc_id            = "vpc-axrsmmrv"
  subnet_id         = "subnet-861wd75e"

  orderly_security_groups = [
    "sg-abc12345"
  ]

  data_disks {
    data_disk_type = "CLOUD_PREMIUM"
    data_disk_size = 50
    encrypt        = false
  }

  tags = {
    tagKey = "tagValue"
  }
}
```

```terraform
resource "tencentcloud_instance" "cvm_postpaid" {
  instance_name     = "cvm_postpaid"
  availability_zone = "ap-guangzhou-7"
  image_id          = "img-9qrfy1xt"
  instance_type     = "S1.SMALL1"
  system_disk_type  = "CLOUD_PREMIUM"
  system_disk_size  = 50
  hostname          = "root"
  project_id        = 0
  vpc_id            = "vpc-axrsmmrv"
  subnet_id         = "subnet-861wd75e"

  security_groups = [
    "sg-abc12345"
  ]

  data_disks {
    data_disk_type = "CLOUD_PREMIUM"
    data_disk_size = 50
    encrypt        = false
  }

  tags = {
    tagKey = "tagValue"
  }
}
```

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

```terraform
resource "tencentcloud_instance" "cvm_postpaid" {
  instance_name     = "cvm_postpaid"
  availability_zone = "ap-guangzhou-7"
  image_id          = "img-9qrfy1xt"
  instance_type     = "S1.SMALL1"
  system_disk_type  = "CLOUD_PREMIUM"
  system_disk_size  = 50
  hostname          = "root"
  project_id        = 0
  vpc_id            = "vpc-axrsmmrv"
  subnet_id         = "subnet-861wd75e"

  data_disks {
    data_disk_type = "CLOUD_PREMIUM"
    data_disk_size = 50
    encrypt        = false
  }

  tags = {
    tagKey = "tagValue"
  }
}
```