---
title: User data contains encoded private key
description: Datadog, the leading service for cloud-scale monitoring.
breadcrumbs: >-
  Docs > Datadog Security > Code Security > Infrastructure as Code (IaC)
  Security > IaC Security Rules > User data contains encoded private key
---

# User data contains encoded private key

{% callout %}
# Important note for users on the following Datadog sites: app.ddog-gov.com, us2.ddog-gov.com

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

{% /callout %}

## Metadata{% #metadata %}

**Id:** `terraform-aws-user-data-contains-encoded-private-key` 

**Provider:** AWS

**Platform:** Terraform

**Severity:** High

**Category:** Encryption

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

- [Provider Reference](https://registry.terraform.io/providers/hashicorp/aws/latest/docs/resources/launch_configuration#user_data_base64)

### Description{% #description %}

AWS Launch Configuration's `user_data_base64` field should never contain private keys, even if base64 encoded, as this encryption method can be easily reversed by attackers. When private keys are exposed in user data, they can be extracted from the instance metadata or discovered through AWS API calls, compromising the security of all systems using those credentials. Instead of embedding private keys directly in user data, as shown in the insecure example `user_data_base64 = "LS0tLS1CRUdJTiBSU0EgUFJJVkFURSBLRVktLS0tLQpzb21lS2V5"`, use AWS secrets management services like AWS Secrets Manager or Systems Manager Parameter Store, or implement a secure alternative where private keys are safely retrieved during instance startup.

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

```terraform
resource "aws_launch_configuration" "negative1" {
  image_id      = data.aws_ami.ubuntu.id
  instance_type = "m4.large"
  spot_price    = "0.001"

  lifecycle {
    create_before_destroy = true
  }
}

resource "aws_launch_configuration" "negative2" {
  image_id      = data.aws_ami.ubuntu.id
  instance_type = "m4.large"
  spot_price    = "0.001"
  user_data_base64 = ""

  lifecycle {
    create_before_destroy = true
  }
}

resource "aws_launch_configuration" "negative3" {
  image_id      = data.aws_ami.ubuntu.id
  instance_type = "m4.large"
  spot_price    = "0.001"
  user_data_base64 = "dGVzdA=="
  
  lifecycle {
    create_before_destroy = true
  }
}

resource "aws_launch_configuration" "negative4" {
  image_id      = data.aws_ami.ubuntu.id
  instance_type = "m4.large"
  spot_price    = "0.001"
  user_data_base64 = null
  
  lifecycle {
    create_before_destroy = true
  }
}
```

```terraform
module "asg" {
  source = "terraform-aws-modules/autoscaling/aws"
  version = "1.0.4"

  # Launch configuration
  lc_name = "example-lc"

  image_id        = "ami-ebd02392"
  instance_type   = "t2.micro"
  security_groups = ["sg-12345678"]

  ebs_block_device = [
    {
      device_name           = "/dev/xvdz"
      volume_type           = "gp2"
      volume_size           = "50"
      delete_on_termination = true
    },
  ]

  root_block_device = [
    {
      volume_size = "50"
      volume_type = "gp2"
    },
  ]

  # Auto scaling group
  asg_name                  = "example-asg"
  vpc_zone_identifier       = ["subnet-1235678", "subnet-87654321"]
  health_check_type         = "EC2"
  min_size                  = 0
  max_size                  = 1
  desired_capacity          = 1
  wait_for_capacity_timeout = 0

  tags = [
    {
      key                 = "Environment"
      value               = "dev"
      propagate_at_launch = true
    },
    {
      key                 = "Project"
      value               = "megasecret"
      propagate_at_launch = true
    },
  ]
}
```

```terraform
module "asg" {
  source = "terraform-aws-modules/autoscaling/aws"
  version = "1.0.4"

  # Launch configuration
  lc_name = "example-lc"

  image_id        = "ami-ebd02392"
  instance_type   = "t2.micro"
  security_groups = ["sg-12345678"]
  user_data_base64 = ""

  ebs_block_device = [
    {
      device_name           = "/dev/xvdz"
      volume_type           = "gp2"
      volume_size           = "50"
      delete_on_termination = true
    },
  ]

  root_block_device = [
    {
      volume_size = "50"
      volume_type = "gp2"
    },
  ]

  # Auto scaling group
  asg_name                  = "example-asg"
  vpc_zone_identifier       = ["subnet-1235678", "subnet-87654321"]
  health_check_type         = "EC2"
  min_size                  = 0
  max_size                  = 1
  desired_capacity          = 1
  wait_for_capacity_timeout = 0

  tags = [
    {
      key                 = "Environment"
      value               = "dev"
      propagate_at_launch = true
    },
    {
      key                 = "Project"
      value               = "megasecret"
      propagate_at_launch = true
    },
  ]
}
```

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

```terraform
resource "aws_launch_configuration" "positive1" {
  image_id      = data.aws_ami.ubuntu.id
  instance_type = "m4.large"
  spot_price    = "0.001"
  user_data_base64 = "LS0tLS1CRUdJTiBSU0EgUFJJVkFURSBLRVktLS0tLQpzb21lS2V5" # someKey

  lifecycle {
    create_before_destroy = true
  }
}
```

```terraform
module "positive2" {
  source = "terraform-aws-modules/autoscaling/aws"
  version = "1.0.4"

  # Launch configuration
  lc_name = "example-lc"

  image_id        = "ami-ebd02392"
  instance_type   = "t2.micro"
  security_groups = ["sg-12345678"]
  user_data_base64 = "LS0tLS1CRUdJTiBSU0EgUFJJVkFURSBLRVktLS0tLQpzb21lS2V5"

  ebs_block_device = [
    {
      device_name           = "/dev/xvdz"
      volume_type           = "gp2"
      volume_size           = "50"
      delete_on_termination = true
    },
  ]

  root_block_device = [
    {
      volume_size = "50"
      volume_type = "gp2"
    },
  ]

  # Auto scaling group
  asg_name                  = "example-asg"
  vpc_zone_identifier       = ["subnet-1235678", "subnet-87654321"]
  health_check_type         = "EC2"
  min_size                  = 0
  max_size                  = 1
  desired_capacity          = 1
  wait_for_capacity_timeout = 0

  tags = [
    {
      key                 = "Environment"
      value               = "dev"
      propagate_at_launch = true
    },
    {
      key                 = "Project"
      value               = "megasecret"
      propagate_at_launch = true
    },
  ]
}
```

```terraform
module "positive3" {
  source = "terraform-aws-modules/autoscaling/aws"
  version = "1.0.4"

  # Launch configuration
  lc_name = "example-lc"

  image_id        = "ami-ebd02392"
  instance_type   = "t2.micro"
  security_groups = ["sg-12345678"]
  user_data_base64 = "LS0tLS1CRUdJTiBPUEVOU1NIIFBSSVZBVEUgS0VZIEJMT0NLLS0tLS0="

  ebs_block_device = [
    {
      device_name           = "/dev/xvdz"
      volume_type           = "gp2"
      volume_size           = "50"
      delete_on_termination = true
    },
  ]

  root_block_device = [
    {
      volume_size = "50"
      volume_type = "gp2"
    },
  ]

  # Auto scaling group
  asg_name                  = "example-asg"
  vpc_zone_identifier       = ["subnet-1235678", "subnet-87654321"]
  health_check_type         = "EC2"
  min_size                  = 0
  max_size                  = 1
  desired_capacity          = 1
  wait_for_capacity_timeout = 0

  tags = [
    {
      key                 = "Environment"
      value               = "dev"
      propagate_at_launch = true
    },
    {
      key                 = "Project"
      value               = "megasecret"
      propagate_at_launch = true
    },
  ]
}
```