support guard duty exports

README.md

@@ -113,6 +113,7 @@ module "aws_logs" {
 | allow\_cloudwatch | Allow Cloudwatch service to export logs to bucket. | `bool` | `false` | no |
 | allow\_config | Allow Config service to log to bucket. | `bool` | `false` | no |
 | allow\_elb | Allow ELB service to log to bucket. | `bool` | `false` | no |
+| allow\_guardduty | Allow GuardDuty service to log to bucket. | `bool` | `false` | no |
 | allow\_nlb | Allow NLB service to log to bucket. | `bool` | `false` | no |
 | allow\_redshift | Allow Redshift service to log to bucket. | `bool` | `false` | no |
 | cloudtrail\_accounts | List of accounts for CloudTrail logs.  By default limits to the current account. | `list(string)` | `[]` | no |
@@ -125,6 +126,7 @@ module "aws_logs" {
 | elb\_accounts | List of accounts for ELB logs.  By default limits to the current account. | `list(string)` | `[]` | no |
 | elb\_logs\_prefix | S3 prefix for ELB logs. | `string` | `"elb"` | no |
 | force\_destroy | A bool that indicates all objects (including any locked objects) should be deleted from the bucket so the bucket can be destroyed without error. | `bool` | `false` | no |
+| guardduty\_logs\_prefixes | S3 key prefixes for GuardDuty logs. | `list(string)` | <pre>[<br>  "guardduty"<br>]</pre> | no |
 | nlb\_account | Account for NLB logs.  By default limits to the current account. | `string` | `""` | no |
 | nlb\_logs\_prefixes | S3 key prefixes for NLB logs. | `list(string)` | <pre>[<br>  "nlb"<br>]</pre> | no |
 | redshift\_logs\_prefix | S3 prefix for RedShift logs. | `string` | `"redshift"` | no |

examples/guardduty/main.tf

@@ -0,0 +1,11 @@
+module "aws_logs" {
+  source = "../../"
+
+  s3_bucket_name          = var.test_name
+  guardduty_logs_prefixes = var.guardduty_logs_prefixes
+  region                  = var.region
+  allow_guardduty         = true
+  default_allow           = false
+
+  force_destroy = var.force_destroy
+}

examples/guardduty/variables.tf

@@ -0,0 +1,15 @@
+variable "test_name" {
+  type = string
+}
+
+variable "region" {
+  type = string
+}
+
+variable "force_destroy" {
+  type = bool
+}
+
+variable "guardduty_logs_prefixes" {
+  type = list(string)
+}

main.tf

@@ -69,6 +69,14 @@ locals {
 
   config_logs_path = var.config_logs_prefix == "" ? "AWSLogs" : "${var.config_logs_prefix}/AWSLogs"
 
+  # Config does a writability check by writing to key "[prefix]/AWSLogs/[accountId]/Config/ConfigWritabilityCheckFile".
+  # When there is an oversize configuration item change notification, Config will write the notification to S3 at the path.
+  # Therefore, you cannot limit the policy to the region.
+  # For example:
+  # config/AWSLogs/[accountId]/Config/global/[year]/[month]/[day]/
+  # OversizedChangeNotification/AWS::IAM::Policy/
+  # [accountId]_Config_global_ChangeNotification_AWS::IAM::Policy_[resourceId]_[timestamp]_[configurationStateId].json.gz
+  # Therefore, do not extend the resource path to include the region as shown in the AWS Console.
   config_resources = sort(formatlist("${local.bucket_arn}/${local.config_logs_path}/%s/Config/*", local.config_accounts))
 
   #
@@ -137,6 +145,33 @@ locals {
   redshift_principal = "arn:${data.aws_partition.current.partition}:iam::${data.aws_redshift_service_account.main.id}:user/logs"
 
   redshift_resource = "${local.bucket_arn}/${var.redshift_logs_prefix}/*"
+
+  #
+  # GuardDuty locals
+  #
+
+  # doesn't support logging to multiple accounts
+  # supports logging to multiple prefixes
+  guardduty_effect = var.default_allow || var.allow_guardduty ? "Allow" : "Deny"
+
+  # if the list of prefixes contains "", set an append_root_prefix flag
+  guardduty_include_root_prefix = contains(var.guardduty_logs_prefixes, "") ? true : false
+
+  # create a list of paths, but remove any prefixes containing "" using compact
+  guardduty_logs_path_temp = formatlist("%s/AWSLogs", compact(var.guardduty_logs_prefixes))
+
+  # now append an "AWSLogs" path to the list if guardduty_include_root_prefix is true
+  guardduty_logs_path = local.guardduty_include_root_prefix ? concat(local.guardduty_logs_path_temp, ["AWSLogs"]) : local.guardduty_logs_path_temp
+
+  # GuardDuty does a writability check using the [prefix]/AWSLogs path,
+  # rather than the full path as shown in the AWS Console.
+  # For example, here is the error you would receive if you used the full path in the bucket policy:
+  # Failed to configure export options because GuardDuty
+  # does not have permission to the KMS key, the S3 bucket, or the specified location in the bucke
+
+  # finally, format the full final resources ARN list
+  guardduty_resources = sort(formatlist("${local.bucket_arn}/%s/*", local.guardduty_logs_path))
+
 }
 
 #
@@ -325,6 +360,37 @@ data "aws_iam_policy_document" "main" {
     resources = [local.bucket_arn]
   }
 
+  #
+  # GuardDuty bucket policies
+  #
+
+  statement {
+    sid    = "guardduty-logs-get-location"
+    effect = local.guardduty_effect
+    principals {
+      type        = "Service"
+      identifiers = ["guardduty.amazonaws.com"]
+    }
+    actions   = ["s3:GetBucketLocation"]
+    resources = [local.bucket_arn]
+  }
+
+  statement {
+    sid    = "guardduty-logs-put-object"
+    effect = local.guardduty_effect
+    principals {
+      type        = "Service"
+      identifiers = ["guardduty.amazonaws.com"]
+    }
+    actions   = ["s3:PutObject"]
+    resources = local.guardduty_resources
+    condition {
+      test     = "StringEquals"
+      variable = "s3:x-amz-acl"
+      values   = ["bucket-owner-full-control"]
+    }
+  }
+
   #
   # Enforce TLS requests only
   #

test/terraform_aws_logs_guardduty_test.go

@@ -0,0 +1,36 @@
+package test
+
+import (
+	"fmt"
+	"strings"
+	"testing"
+
+	"github.com/gruntwork-io/terratest/modules/aws"
+	"github.com/gruntwork-io/terratest/modules/random"
+	"github.com/gruntwork-io/terratest/modules/terraform"
+	test_structure "github.com/gruntwork-io/terratest/modules/test-structure"
+)
+
+func TestTerraformAwsLogsGuardDuty(t *testing.T) {
+	t.Parallel()
+
+	tempTestFolder := test_structure.CopyTerraformFolderToTemp(t, "../", "examples/guardduty")
+	testName := fmt.Sprintf("terratest-aws-logs-%s", strings.ToLower(random.UniqueId()))
+	awsRegion := "us-west-2"
+
+	terraformOptions := &terraform.Options{
+		TerraformDir: tempTestFolder,
+		Vars: map[string]interface{}{
+			"region":            awsRegion,
+			"test_name":         testName,
+			"force_destroy":     true,
+			"guardduty_logs_prefixes": []string{testName},
+		},
+		EnvVars: map[string]string{
+			"AWS_DEFAULT_REGION": awsRegion,
+		},
+	}
+
+	defer terraform.Destroy(t, terraformOptions)
+	terraform.InitAndApply(t, terraformOptions)
+}

variables.tf

@@ -100,6 +100,12 @@ variable "allow_redshift" {
   type        = bool
 }
 
+variable "allow_guardduty" {
+  description = "Allow GuardDuty service to log to bucket."
+  default     = false
+  type        = bool
+}
+
 variable "create_public_access_block" {
   description = "Whether to create a public_access_block restricting public access to the bucket."
   default     = true
@@ -153,3 +159,9 @@ variable tags {
   default     = {}
   description = "A mapping of tags to assign to the logs bucket. Please note that tags with a conflicting key will not override the original tag."
 }
+
+variable "guardduty_logs_prefixes" {
+  description = "S3 key prefixes for GuardDuty logs."
+  default     = ["guardduty"]
+  type        = list(string)
+}