S3 Bucket Without Server-side-encryption

• Query id: b2e8752c-3497-4255-98d2-e4ae5b46bbf5
• Query name: S3 Bucket Without Server-side-encryption
• Platform: CloudFormation
• Severity: High
• Category: Encryption
• CWE: 311
• URL: Github

Description

S3 Buckets should have server-side encryption at rest enabled to protect sensitive data
Documentation

Code samples

Code samples with security vulnerabilities

Positive test num. 1 - yaml file

#this is a problematic code where the query should report a result(s)
AWSTemplateFormatVersion: '2010-09-09'
Description: S3 bucket without default encryption
Resources:
  S3Bucket:
    Type: 'AWS::S3::Bucket'
    Properties:
      BucketName:
        'Fn::Sub': 'bucket-${AWS::Region}-${AWS::AccountId}'
    DeletionPolicy: Delete

Positive test num. 2 - json file

{
  "Resources": {
    "S3Bucket": {
      "Type": "AWS::S3::Bucket",
      "Properties": {
        "BucketName": {
          "Fn::Sub": "bucket-${AWS::Region}-${AWS::AccountId}"
        }
      },
      "DeletionPolicy": "Delete"
    }
  },
  "AWSTemplateFormatVersion": "2010-09-09",
  "Description": "S3 bucket without default encryption"
}

Code samples without security vulnerabilities

Negative test num. 1 - yaml file

#this code is a correct code for which the query should not find any result
AWSTemplateFormatVersion: '2010-09-09'
Description: S3 bucket with default encryption
Resources:
  EncryptedS3Bucket:
    Type: 'AWS::S3::Bucket'
    Properties:
      BucketName:
        'Fn::Sub': 'encryptedbucket-${AWS::Region}-${AWS::AccountId}'
      BucketEncryption:
        ServerSideEncryptionConfiguration:
          - ServerSideEncryptionByDefault:
              SSEAlgorithm: 'aws:kms'
              KMSMasterKeyID: KMS-KEY-ARN
    DeletionPolicy: Delete

Negative test num. 2 - json file

{
  "AWSTemplateFormatVersion": "2010-09-09",
  "Description": "S3 bucket with default encryption",
  "Resources": {
    "EncryptedS3Bucket": {
      "Type": "AWS::S3::Bucket",
      "Properties": {
        "BucketName": {
          "Fn::Sub": "encryptedbucket-${AWS::Region}-${AWS::AccountId}"
        },
        "BucketEncryption": {
          "ServerSideEncryptionConfiguration": [
            {
              "ServerSideEncryptionByDefault": {
                "SSEAlgorithm": "aws:kms",
                "KMSMasterKeyID": "KMS-KEY-ARN"
              }
            }
          ]
        }
      },
      "DeletionPolicy": "Delete"
    }
  }
}