CloudFront distributions should use SNI to serve HTTPS requests¶

This control checks if AWS CloudFront distributions are using a custom SSL/TLS certificate and are configured to use SNI to serve HTTPS requests. This control fails if a custom SSL/TLS certificate is associated but the SSL/TLS support method is a dedicated IP address.

How to fix¶

Attribute viewer_certificate[0].ssl_support_method of aws_cloudfront_distribution must be "sni-only".

Implementation options¶

Choose the option that matches how you manage Terraform. All options satisfy this control.

Option 1: Compliance.tf module (recommended)¶

Use the compliance.tf registry module to get this control enforced by default. This control is mapped to the frameworks shown in the tabs above. To begin, see get started with compliance.tf.

module "cloudfront" {
  source  = "nistcsfv11.compliance.tf/terraform-aws-modules/cloudfront/aws"
  version = ">=6.0.0,<7.0.0"

  comment = "My CloudFront distribution"
  default_cache_behavior = {
    target_origin_id       = "s3"
    viewer_protocol_policy = "redirect-to-https"
  }
  enabled = true
  origin = {
    s3 = {
      domain_name = "mybucket.s3.amazonaws.com"
    }
  }
}

module "cloudfront" {
  source  = "pcidss.compliance.tf/terraform-aws-modules/cloudfront/aws"
  version = ">=6.0.0,<7.0.0"

  comment = "My CloudFront distribution"
  default_cache_behavior = {
    target_origin_id       = "s3"
    viewer_protocol_policy = "redirect-to-https"
  }
  enabled = true
  origin = {
    s3 = {
      domain_name = "mybucket.s3.amazonaws.com"
    }
  }
}

Option 2: Open source module (terraform-aws-modules)¶

If you use terraform-aws-modules/cloudfront/aws, configure the required module inputs to satisfy this control. You can later migrate to the compliance.tf module with minimal changes because it is compatible by design.

module "cloudfront" {
  source  = "terraform-aws-modules/cloudfront/aws"
  version = ">=6.0.0,<7.0.0"

  comment = "My CloudFront distribution"
  default_cache_behavior = {
    target_origin_id       = "s3"
    viewer_protocol_policy = "redirect-to-https"
  }
  enabled = true
  origin = {
    s3 = {
      domain_name = "mybucket.s3.amazonaws.com"
    }
  }

  viewer_certificate = {
    ssl_support_method = "sni-only"
  }
}

Option 3: Terraform AWS provider resources¶

If you manage resources directly, configure the relevant Terraform AWS provider resources to meet this control. See docs for the resources involved: aws_cloudfront_distribution.

resource "aws_cloudfront_distribution" "this" {
  default_cache_behavior {
    allowed_methods           = ["GET", "HEAD"]
    cached_methods            = ["GET", "HEAD"]
    field_level_encryption_id = "E1EXAMPLE"

    forwarded_values {
      cookies {
        forward = "none"
      }
      query_string = false
    }

    target_origin_id       = "S3Origin"
    viewer_protocol_policy = "redirect-to-https"
  }
  default_root_object = "index.html"
  enabled             = true

  logging_config {
    bucket = "logging-bucket.s3.amazonaws.com"
  }

  origin {
    domain_name = "example.s3.amazonaws.com"
    origin_id   = "S3Origin"
  }

  restrictions {
    geo_restriction {
      locations        = ["US", "CA", "GB"]
      restriction_type = "whitelist"
    }
  }

  web_acl_id = "arn:aws:wafv2:us-east-1:123456789012:global/webacl/example/id"

  viewer_certificate {
    acm_certificate_arn      = "arn:aws:acm:us-east-1:123456789012:certificate/example"
    minimum_protocol_version = "TLSv1.2_2021"
    ssl_support_method       = "sni-only"
  }
}

Tool mappings¶

Use these identifiers to cross-reference this control across tools, reports, and evidence.

• Compliance.tf (CTF) Control: cloudfront_distribution_sni_enabled

• AWS Config Managed Rule: CLOUDFRONT_SNI_ENABLED

• Powerpipe Control: aws_compliance.control.cloudfront_distribution_sni_enabled