---
title: S3 bucket allows public policy
description: Datadog, the leading service for cloud-scale monitoring.
breadcrumbs: >-
  Docs > Datadog Security > Code Security > Infrastructure as Code (IaC)
  Security > IaC Security Rules > S3 bucket allows public policy
---

# S3 bucket allows public policy

{% 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" /%}).
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{% /callout %}

## Metadata{% #metadata %}

**Id:** `terraform-aws-s3-bucket-with-public-policy` 

**Provider:** AWS

**Platform:** Terraform

**Severity:** High

**Category:** Access Control

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

- [Provider Reference](https://registry.terraform.io/providers/hashicorp/aws/latest/docs/resources/s3_bucket_public_access_block)

### Description{% #description %}

S3 buckets should block public policies to prevent unauthorized access to bucket contents. When the `block_public_policy` attribute is set to false or not defined in the `aws_s3_bucket_public_access_block` resource, attackers could potentially attach public policies to the bucket, exposing sensitive data to the internet. To secure your S3 bucket, ensure that `block_public_policy` is set to `true`, as shown in the following example:

```terraform
resource "aws_s3_bucket_public_access_block" "example" {
  bucket = aws_s3_bucket.example.id
  block_public_acls   = true
  block_public_policy = true
  ignore_public_acls  = false
}
```

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

```terraform
resource "aws_s3_bucket" "negative1" {
  bucket = "example"
}

resource "aws_s3_bucket_public_access_block" "negative2" {
  bucket = aws_s3_bucket.example.id

  block_public_acls   = true
  block_public_policy = true
  ignore_public_acls  = false
}
```

```terraform
module "s3_bucket" {
  source = "terraform-aws-modules/s3-bucket/aws"
  version = "3.7.0"

  bucket = "my-s3-bucket"
  acl    = "private"
  restrict_public_buckets = true
  block_public_acls = true
  block_public_policy = true

  versioning = {
    enabled = true
  }

  policy = <<POLICY
{
  "Version": "2012-10-17",
  "Id": "MYBUCKETPOLICY",
  "Statement": [
    {
      "Sid": "IPAllow",
      "Effect": "Deny",
      "Action": "s3:*",
      "Resource": "arn:aws:s3:::my_tf_test_bucket/*",
      "Condition": {
         "IpAddress": {"aws:SourceIp": "8.8.8.8/32"}
      }
    }
  ]
}
POLICY
}
```

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

```terraform
resource "aws_s3_bucket" "positive1" {
  bucket = "example"
}

resource "aws_s3_bucket_public_access_block" "positive2" {
  bucket = aws_s3_bucket.example.id

  block_public_acls   = true
  block_public_policy = false
  ignore_public_acls  = false
}

// comment
// comment
// comment
// comment
// comment
resource "aws_s3_bucket_public_access_block" "positive3" {
  bucket = aws_s3_bucket.example.id

  block_public_acls   = true
  ignore_public_acls  = false
}
```

```terraform
module "s3_bucket" {
  source = "terraform-aws-modules/s3-bucket/aws"
  version = "3.7.0"

  bucket = "my-s3-bucket"
  acl    = "private"
  restrict_public_buckets = true
  block_public_acls = true
  block_public_policy = false

  versioning = {
    enabled = true
  }

  policy = <<POLICY
{
  "Version": "2012-10-17",
  "Id": "MYBUCKETPOLICY",
  "Statement": [
    {
      "Sid": "IPAllow",
      "Effect": "Deny",
      "Action": "s3:*",
      "Resource": "arn:aws:s3:::my_tf_test_bucket/*",
      "Condition": {
         "IpAddress": {"aws:SourceIp": "8.8.8.8/32"}
      }
    }
  ]
}
POLICY
}
```

```terraform
module "s3_bucket" {
  source = "terraform-aws-modules/s3-bucket/aws"
  version = "3.7.0"

  bucket = "my-s3-bucket"
  acl    = "private"
  restrict_public_buckets = true
  block_public_acls = true

  versioning = {
    enabled = true
  }

  policy = <<POLICY
{
  "Version": "2012-10-17",
  "Id": "MYBUCKETPOLICY",
  "Statement": [
    {
      "Sid": "IPAllow",
      "Effect": "Deny",
      "Action": "s3:*",
      "Resource": "arn:aws:s3:::my_tf_test_bucket/*",
      "Condition": {
         "IpAddress": {"aws:SourceIp": "8.8.8.8/32"}
      }
    }
  ]
}
POLICY
}
```