---
title: S3 bucket ACL allows read to all users
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 ACL allows read to all users
---

# S3 bucket ACL allows read to all users

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## Metadata{% #metadata %}

**Id:** `cloudformation-aws-s3-bucket-acl-allows-read-to-all-users` 

**Provider:** AWS

**Platform:** CloudFormation

**Severity:** High

**Category:** Access Control

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

- [Provider Reference](https://docs.aws.amazon.com/AWSCloudFormation/latest/UserGuide/aws-properties-s3-bucket.html)

### Description{% #description %}

S3 buckets with a publicly readable ACL allow any internet user to list and download objects. This can lead to data leakage, accidental exposure of sensitive information, and compliance violations. This rule checks `AWS::S3::Bucket` resources and flags buckets whose `Properties.AccessControl` is set to `PublicRead`. To remediate, set `AccessControl` to `Private` or remove the ACL and enable S3 Block Public Access controls. If you must serve public content, use a CDN (CloudFront) with an origin access identity or a narrowly scoped bucket policy instead of a public ACL.

Secure CloudFormation example:

```yaml
MySecureBucket:
  Type: AWS::S3::Bucket
  Properties:
    BucketName: my-secure-bucket
    AccessControl: Private
    PublicAccessBlockConfiguration:
      BlockPublicAcls: true
      IgnorePublicAcls: true
      BlockPublicPolicy: true
      RestrictPublicBuckets: true
```

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

```yaml
AWSTemplateFormatVersion: 2010-09-09
Description: Creating S3 bucket
Resources:
  JenkinsArtifacts03:
    Type: AWS::S3::Bucket
    Properties:
      AccessControl: BucketOwnerFullControl
      BucketName: jenkins-artifacts
      VersioningConfiguration:
        Status: Enabled
      Tags:
        - Key: CostCenter
          Value: ITEngineering
        - Key: Type
          Value: CICD
```

```yaml
AWSTemplateFormatVersion: 2010-09-09
Description: Creating S3 bucket
Resources:
  JenkinsArtifacts04:
    Type: AWS::S3::Bucket
    Properties:
      AccessControl: Private
      BucketName: jenkins-secret-artifacts
      VersioningConfiguration:
        Status: Enabled
      Tags:
        - Key: CostCenter
          Value: ITEngineering
```

```yaml
AWSTemplateFormatVersion: 2010-09-09
Description: Creating S3 bucket
Resources:
  JenkinsArtifacts05:
    Type: AWS::S3::Bucket
    Properties:
      AccessControl: PublicReadWrite
      BucketName: jenkins-secret-artifacts2
      VersioningConfiguration:
        Status: Enabled
      Tags:
        - Key: CostCenter
          Value: ITEngineering
```

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

```yaml
AWSTemplateFormatVersion: 2010-09-09
Description: Creating S3 bucket
Resources:
  JenkinsArtifacts01:
    Type: AWS::S3::Bucket
    Properties:
      AccessControl: PublicRead
      BucketName: jenkins-artifacts
      Tags:
        - Key: CostCenter
          Value: ITEngineering
```

```yaml
AWSTemplateFormatVersion: 2010-09-09
Description: Creating S3 bucket
Resources:
  StaticPage01:
    Type: AWS::S3::Bucket
    Properties:
      AccessControl: PublicRead
      BucketName: public-read-static-page01
      WebsiteConfiguration:
        ErrorDocument: 404.html
        IndexDocument: index.html
      Tags:
        - Key: CostCenter
          Value: ITEngineering
```

```yaml
AWSTemplateFormatVersion: 2010-09-09
Description: Creating S3 bucket
Resources:
  JenkinsArtifacts02:
    Type: AWS::S3::Bucket
    Properties:
      AccessControl: PublicRead
      BucketName: jenkins-artifacts-block-public
      PublicAccessBlockConfiguration:
        BlockPublicPolicy: false
      VersioningConfiguration:
        Status: Enabled
      Tags:
        - Key: CostCenter
          Value: ITEngineering
        - Key: Type
          Value: CICD
```