Insecure Network Communication

Why is this important?

Ensuring that the data in transit is secured between users and your application is the most fundamental security requirement. If this security control is not in place then all bets are off and attackers have many ways to attack your users.

Check out this video for a high-level explanation:

Unencrypted MSK Broker

AWS offers a Managed Streaming for Kafka cluster service, which may transmit data in clear-text.

More information can be found here:

• MSK Cluster - Encryption Info Arguments

Option A: Ensure MSK Encryption in Transit

1. Go through the issues that GuardRails identified.
2. Locate the aws_msk_cluster resource.

resource "aws_msk_cluster" "example" {
  cluster_name           = "example"
  kafka_version          = "2.4.1"
  number_of_broker_nodes = 3

  broker_node_group_info {
    instance_type   = "kafka.m5.large"
    ebs_volume_size = 1000
    client_subnets = [
      aws_subnet.subnet_az1.id,
      aws_subnet.subnet_az2.id,
      aws_subnet.subnet_az3.id,
    ]
    security_groups = [aws_security_group.sg.id]
  }
}

3. Ensure that the aws_msk_cluster resource includes an encryption_info object, for example like shown below.

resource "aws_msk_cluster" "example" {
  cluster_name           = "example"
  ...
  encryption_info {
    encryption_at_rest_kms_key_arn = aws_kms_key.kms.arn
  }
}

Unencrypted Kinesis Stream

AWS offers a Kinesis Stream resource, which is a managed service that scales elastically for real-time processing of streaming big data. This service may transmit data in clear-text.

More information can be found here:

• Kinesis Stream - Encryption Type Arguments

Option A: Ensure Kinesis Stream Encryption in Transit

1. Go through the issues that GuardRails identified.
2. Locate the aws_kinesis_stream resource.

resource "aws_kinesis_stream" "test_stream" {
  name             = "terraform-kinesis-test"
  shard_count      = 1
  retention_period = 48

  shard_level_metrics = [
    "IncomingBytes",
    "OutgoingBytes",
  ]

  tags = {
    Environment = "test"
  }
}

3. Ensure that the aws_kinesis_stream resource includes the encryption_type argument set to KMS.

resource "aws_kinesis_stream" "test_stream" {
  name             = "terraform-kinesis-test"
  shard_count      = 1
  retention_period = 48
  encryption_type  = "KMS"
  ...
}

Ensure Encryption in Transit

Certain services communicate via HTTP unless configured otherwise.

Option A: Ensure AWS Load Balancer is using HTTPS

1. Go through the issues that GuardRails identified.
2. Locate the aws_lb_listener resource.

resource "aws_lb_listener" "front_end" {
  load_balancer_arn = aws_lb.front_end.arn
  port              = "80"
  protocol          = "HTTP"
  ssl_policy        = "ELBSecurityPolicy-2016-08"
  certificate_arn   = "arn:aws:iam::187416307283:server-certificate/test_cert_rab3wuqwgja25ct3n4jdj2tzu4"

  default_action {
    type             = "forward"
    target_group_arn = aws_lb_target_group.front_end.arn
  }
}

3. Update the protocol to either HTTPS or TLS.

Option B: Ensure CloudFront is using HTTPS

1. Go through the issues that GuardRails identified.
2. Locate the aws_cloudfront_distribution resource.

resource "aws_cloudfront_distribution" "s3_distribution" {
  origin {
    domain_name = aws_s3_bucket.b.bucket_regional_domain_name
    ...
  }

  enabled             = true
  ...

  aliases = ["mysite.example.com", "yoursite.example.com"]

  default_cache_behavior {
    allowed_methods  = ["DELETE", "GET", "HEAD", "OPTIONS", "PATCH", "POST", "PUT"]
    cached_methods   = ["GET", "HEAD"]
    target_origin_id = local.s3_origin_id

    forwarded_values {
      query_string = false

      cookies {
        forward = "none"
      }
    }

    viewer_protocol_policy = "allow-all"
    min_ttl                = 0
    default_ttl            = 3600
    max_ttl                = 86400
  }

3. If the viewer_protocol_policy is missing or set to allow-all, then change it to either https-only or redirect-to-https.

Ensure Secure SSL/TLS Configuration

Even though SSL/TLS is configured for certain services, it may be configured insecurely and as a result increase the risk of getting intercepted.

Option A: Use correct SSL/TLS policy for AWS ELB

1. Go through the issues that GuardRails identified.
2. Identify the SSL/TLS related for the aws_lb_listener.

resource "aws_lb_listener" "front_end" {
  load_balancer_arn = aws_lb.front_end.arn
  port              = "443"
  protocol          = "HTTPS"
  ssl_policy        = "ELBSecurityPolicy-2016-08"
  certificate_arn   = "arn:aws:iam::187416307283:server-certificate/test_cert_rab3wuqwgja25ct3n4jdj2tzu4"

  default_action {
    type             = "forward"
    target_group_arn = aws_lb_target_group.front_end.arn
  }
}

3. Make sure to avoid the following SSL Policies:

ELBSecurityPolicy-2015-05
ELBSecurityPolicy-TLS-1-0-2015-04
ELBSecurityPolicy-2016-08
ELBSecurityPolicy-TLS-1-1-2017-01

Instead, it is recommended to use:

TLS-1-2-2017-01

4. Test it
5. Ship it 🚢 and relax 🌴

Option B: Use secure minimum_protocol_version of TLS for CloudFront

1. Go through the issues that GuardRails identified.
2. Identify the SSL/TLS related for the aws_cloudfront_distribution.
3. Ensure that the viewer_certificate is configured securely.

viewer_certificate {
  ...
  minimum_protocol_version        = TLSv1.2_2019
}

Option C: Use correct security policy for AWS API Gateway

1. Go through the issues that GuardRails identified.
2. Locate the aws_api_gateway_domain_name resource and the security_policy if it exists.

resource "aws_api_gateway_domain_name" "example" {
  domain_name               = "api.example.com"
  regional_certificate_name = "example-api"
  ...
}

3. Change the security_policy to TLS_1_2.

resource "aws_api_gateway_domain_name" "example" {
  domain_name               = "api.example.com"
  regional_certificate_name = "example-api"
  ...
  security_policy = "TLS_1_2"
}