S3 Bucket ACL Allows Read to Any Authenticated User

• Query id: 835d5497-a526-4aea-a23f-98a9afd1635f
• Query name: S3 Bucket ACL Allows Read to Any Authenticated User
• Platform: CloudFormation
• Severity: High
• Category: Access Control
• URL: Github

Description

S3 Buckets should not be readable to any authenticated user
Documentation

Code samples

Code samples with security vulnerabilities

Positive test num. 1 - yaml file

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

Positive test num. 2 - yaml file

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

Positive test num. 3 - yaml file

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

Positive test num. 4 - yaml file

AWSTemplateFormatVersion: 2010-09-09
Description: Creating S3 bucket
Resources:
  S3BucketForWebsiteContent:
    Type: AWS::S3::Bucket
    Properties:
      AccessControl: AuthenticatedRead
      WebsiteConfiguration:
        IndexDocument: index.html
        ErrorDocument: error.html

Positive test num. 5 - json file

{
  "AWSTemplateFormatVersion": "2010-09-09T00:00:00Z",
  "Description": "Creating S3 bucket",
  "Resources": {
    "JenkinsArtifacts01": {
      "Properties": {
        "AccessControl": "AuthenticatedRead",
        "BucketName": "jenkins-artifacts",
        "Tags": [
          {
            "Value": "ITEngineering",
            "Key": "CostCenter"
          }
        ]
      },
      "Type": "AWS::S3::Bucket"
    }
  }
}

Positive test num. 6 - json file

{
  "AWSTemplateFormatVersion": "2010-09-09T00:00:00Z",
  "Description": "Creating S3 bucket",
  "Resources": {
    "StaticPage01": {
      "Properties": {
        "AccessControl": "AuthenticatedRead",
        "BucketName": "public-read-static-page01",
        "WebsiteConfiguration": {
          "ErrorDocument": "404.html",
          "IndexDocument": "index.html"
        },
        "Tags": [
          {
            "Key": "CostCenter",
            "Value": "ITEngineering"
          }
        ]
      },
      "Type": "AWS::S3::Bucket"
    }
  }
}

Positive test num. 7 - json file

{
  "Description": "Creating S3 bucket",
  "Resources": {
    "JenkinsArtifacts02": {
      "Type": "AWS::S3::Bucket",
      "Properties": {
        "VersioningConfiguration": {
          "Status": "Enabled"
        },
        "Tags": [
          {
            "Key": "CostCenter",
            "Value": "ITEngineering"
          },
          {
            "Key": "Type",
            "Value": "CICD"
          }
        ],
        "AccessControl": "AuthenticatedRead",
        "BucketName": "jenkins-artifacts-block-public",
        "PublicAccessBlockConfiguration": {
          "BlockPublicPolicy": false
        }
      }
    }
  },
  "AWSTemplateFormatVersion": "2010-09-09T00:00:00Z"
}

Positive test num. 8 - json file

{
  "Description": "Creating S3 bucket",
  "Resources": {
    "S3BucketForWebsiteContent": {
      "Type": "AWS::S3::Bucket",
      "Properties": {
        "AccessControl": "AuthenticatedRead",
        "WebsiteConfiguration": {
          "IndexDocument": "index.html",
          "ErrorDocument": "error.html"
        }
      }
    }
  },
  "AWSTemplateFormatVersion": "2010-09-09T00:00:00Z"
}

Code samples without security vulnerabilities

Negative test num. 1 - yaml file

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

Negative test num. 2 - yaml file

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: ''

Negative test num. 3 - yaml file

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

Negative test num. 4 - yaml file

AWSTemplateFormatVersion: 2010-09-09
Description: Creating S3 bucket
Resources:
  StaticPage03:
    Type: AWS::S3::Bucket
    Properties:
      AccessControl: PublicRead
      BucketName: public-read-static-page
      WebsiteConfiguration:
        ErrorDocument: 404.html
        IndexDocument: index.html
      Tags:
        - Key: CostCenter
          Value: ITEngineering
Outputs:
  WebsiteURL:
    Value:
      Fn::GetAtt:
        - StaticPage03
        - WebsiteURL
    Description: URL for website hosted on S3
  S3BucketSecureURL:
    Value:
      Fn::Join:
        - ""
        - - https://
          - Fn::GetAtt:
              - StaticPage03
              - DomainName
    Description: Name of S3 bucket to hold website content

Negative test num. 5 - json file

{
  "AWSTemplateFormatVersion": "2010-09-09T00:00:00Z",
  "Description": "Creating S3 bucket",
  "Resources": {
    "JenkinsArtifacts03": {
      "Type": "AWS::S3::Bucket",
      "Properties": {
        "Tags": [
          {
            "Key": "CostCenter",
            "Value": "ITEngineering"
          },
          {
            "Key": "Type",
            "Value": "CICD"
          }
        ],
        "AccessControl": "BucketOwnerFullControl",
        "BucketName": "jenkins-artifacts",
        "VersioningConfiguration": {
          "Status": "Enabled"
        }
      }
    }
  }
}

Negative test num. 6 - json file

{
  "AWSTemplateFormatVersion": "2010-09-09T00:00:00Z",
  "Description": "Creating S3 bucket",
  "Resources": {
    "JenkinsArtifacts04": {
      "Type": "AWS::S3::Bucket",
      "Properties": {
        "AccessControl": "Private",
        "BucketName": "jenkins-secret-artifacts",
        "VersioningConfiguration": {
          "Status": "Enabled"
        },
        "Tags": [
          {
            "Key": "CostCenter",
            "Value": ""
          }
        ]
      }
    }
  }
}

Negative test num. 7 - json file

{
  "AWSTemplateFormatVersion": "2010-09-09T00:00:00Z",
  "Description": "Creating S3 bucket",
  "Resources": {
    "JenkinsArtifacts05": {
      "Properties": {
        "BucketName": "jenkins-secret-artifacts2",
        "VersioningConfiguration": {
          "Status": "Enabled"
        },
        "Tags": [
          {
            "Value": "ITEngineering",
            "Key": "CostCenter"
          }
        ],
        "AccessControl": "PublicReadWrite"
      },
      "Type": "AWS::S3::Bucket"
    }
  }
}

Negative test num. 8 - json file

{
  "Resources": {
    "StaticPage03": {
      "Type": "AWS::S3::Bucket",
      "Properties": {
        "Tags": [
          {
            "Key": "CostCenter",
            "Value": "ITEngineering"
          }
        ],
        "AccessControl": "PublicRead",
        "BucketName": "public-read-static-page",
        "WebsiteConfiguration": {
          "ErrorDocument": "404.html",
          "IndexDocument": "index.html"
        }
      }
    }
  },
  "Outputs": {
    "WebsiteURL": {
      "Value": {
        "Fn::GetAtt": [
          "StaticPage03",
          "WebsiteURL"
        ]
      },
      "Description": "URL for website hosted on S3"
    },
    "S3BucketSecureURL": {
      "Description": "Name of S3 bucket to hold website content",
      "Value": {
        "Fn::Join": [
          "",
          [
            "https://",
            {
              "Fn::GetAtt": [
                "StaticPage03",
                "DomainName"
              ]
            }
          ]
        ]
      }
    }
  },
  "AWSTemplateFormatVersion": "2010-09-09T00:00:00Z",
  "Description": "Creating S3 bucket"
}