CloudTrail Log Files S3 Bucket with Logging Disabled

• Query id: ee9e50e8-b2ed-4176-ad42-8fc0cf7593f4
• Query name: CloudTrail Log Files S3 Bucket with Logging Disabled
• Platform: Terraform
• Severity: Medium
• Category: Observability
• CWE: 778
• URL: Github

Description

CloudTrail Log Files S3 Bucket should have 'logging' enabled
Documentation

Code samples

Code samples with security vulnerabilities

Positive test num. 1 - tf file

provider "aws" {
  region = "us-east-1"
}

terraform {
  required_providers {
    aws = {
      source  = "hashicorp/aws"
      version = "~> 3.0"
    }
  }
}

data "aws_caller_identity" "current" {}

resource "aws_cloudtrail" "foobar" {
  name                          = "tf-trail-foobar"
  s3_bucket_name                = aws_s3_bucket.foo.id
  s3_key_prefix                 = "prefix"
  include_global_service_events = false
}

resource "aws_s3_bucket" "foo" {
  bucket        = "tf-test-trail"
  force_destroy = true

  policy = <<POLICY
{
    "Version": "2012-10-17",
    "Statement": [
        {
            "Sid": "AWSCloudTrailAclCheck",
            "Effect": "Allow",
            "Principal": {
              "Service": "cloudtrail.amazonaws.com"
            },
            "Action": "s3:GetBucketAcl",
            "Resource": "arn:aws:s3:::tf-test-trail"
        },
        {
            "Sid": "AWSCloudTrailWrite",
            "Effect": "Allow",
            "Principal": {
              "Service": "cloudtrail.amazonaws.com"
            },
            "Action": "s3:PutObject",
            "Resource": "arn:aws:s3:::tf-test-trail/prefix/AWSLogs/${data.aws_caller_identity.current.account_id}/*",
            "Condition": {
                "StringEquals": {
                    "s3:x-amz-acl": "bucket-owner-full-control"
                }
            }
        }
    ]
}
POLICY
}

Positive test num. 2 - tf file

module "foo" {
  source = "terraform-aws-modules/s3-bucket/aws"
  version = "0.0.1"
  acl    = "private"
  bucket        = "foo"
  force_destroy = true

  policy = <<POLICY
{
    "Version": "2012-10-17",
    "Statement": [
        {
            "Sid": "AWSCloudTrailAclCheck",
            "Effect": "Allow",
            "Principal": {
              "Service": "cloudtrail.amazonaws.com"
            },
            "Action": "s3:GetBucketAcl",
            "Resource": "arn:aws:s3:::tf-test-trail"
        },
        {
            "Sid": "AWSCloudTrailWrite",
            "Effect": "Allow",
            "Principal": {
              "Service": "cloudtrail.amazonaws.com"
            },
            "Action": "s3:PutObject",
            "Resource": "arn:aws:s3:::tf-test-trail/prefix/AWSLogs/${data.aws_caller_identity.current.account_id}/*",
            "Condition": {
                "StringEquals": {
                    "s3:x-amz-acl": "bucket-owner-full-control"
                }
            }
        }
    ]
}
POLICY

  versioning_inputs = [
    {
      enabled = true
      mfa_delete = null
    },
  ]
}

resource "aws_cloudtrail" "foobar" {
  name                          = "tf-trail-foobar"
  s3_bucket_name                = aws_s3_bucket.foo.id
  s3_key_prefix                 = "prefix"
  include_global_service_events = false
}

Positive test num. 3 - tf file

terraform {
  required_providers {
    aws = {
      source = "hashicorp/aws"
      version = "4.2.0"
    }
  }
}

provider "aws" {
  # Configuration options
}

resource "aws_cloudtrail" "foobar2" {
  name                          = "tf-trail-foobar"
  s3_bucket_name                = aws_s3_bucket.bb.id
  s3_key_prefix                 = "prefix"
  include_global_service_events = false
}

resource "aws_s3_bucket" "bb" {
  bucket = "my-tf-example-bucket"
}

Code samples without security vulnerabilities

Negative test num. 1 - tf file

provider "aws" {
  region = "us-east-1"
}

terraform {
  required_providers {
    aws = {
      source  = "hashicorp/aws"
      version = "~> 3.0"
    }
  }
}

data "aws_caller_identity" "current2" {}

resource "aws_cloudtrail" "foobar2" {
  name                          = "tf-trail-foobar"
  s3_bucket_name                = aws_s3_bucket.foo2.id
  s3_key_prefix                 = "prefix"
  include_global_service_events = false
}

resource "aws_s3_bucket" "log_bucket" {
  bucket = "my-tf-log-bucket"
  acl    = "log-delivery-write"
}


resource "aws_s3_bucket" "foo2" {
  bucket = "my-tf-test-bucket"
  acl    = "private"

  logging {
    target_bucket = aws_s3_bucket.log_bucket.id
    target_prefix = "log/"
  }
}

Negative test num. 2 - tf file

module "s3_bucket" {
  source = "terraform-aws-modules/s3-bucket/aws"
  version = "0.0.1"
  bucket = "s3-tf-example-versioning"
  acl    = "private"
  logging {
    target_bucket = aws_s3_bucket.log_bucket.id
    target_prefix = "log/"
  }

  versioning_inputs = [
    {
      enabled = true
      mfa_delete = null
    },
  ]
}

Negative test num. 3 - tf file

terraform {
  required_providers {
    aws = {
      source = "hashicorp/aws"
      version = "4.2.0"
    }
  }
}

provider "aws" {
  # Configuration options
}

resource "aws_cloudtrail" "foobar2" {
  name                          = "tf-trail-foobar"
  s3_bucket_name                = aws_s3_bucket.bbb.id
  s3_key_prefix                 = "prefix"
  include_global_service_events = false
}

resource "aws_s3_bucket" "bbb" {
  bucket = "my-tf-example-bucket"
}

resource "aws_s3_bucket_logging" "example" {
  bucket = aws_s3_bucket.bbb.id

  target_bucket = aws_s3_bucket.log_bucket.id
  target_prefix = "log/"
}