S3 Bucket Logging Disabled

• Query id: 4552b71f-0a2a-4bc4-92dd-ed7ec1b4674c
• Query name: S3 Bucket Logging Disabled
• Platform: CloudFormation
• Severity: Medium
• Category: Observability
• URL: Github

Description

Server Access Logging should be enabled on S3 Buckets so that all changes are logged and trackable
Documentation

Code samples

Code samples with security vulnerabilities

Positive test num. 1 - yaml file

AWSTemplateFormatVersion: "2010-09-09"
Description: A sample template
Resources:
  mybucket:
    Type: "AWS::S3::Bucket"
    DeletionPolicy: Retain
    Properties:
      ReplicationConfiguration:
        Role:
          "Fn::GetAtt":
            - WorkItemBucketBackupRole
            - Arn
        Rules:
          - Destination:
              Bucket:
                "Fn::Join":
                  - ""
                  - - "arn:aws:s3:::"
                    - "Fn::Join":
                        - "-"
                        - - Ref: "AWS::Region"
                          - Ref: "AWS::StackName"
                          - replicationbucket
              StorageClass: STANDARD
            Id: Backup
            Prefix: ""
            Status: Enabled
      VersioningConfiguration:
        Status: Enabled
  WorkItemBucketBackupRole:
    Type: "AWS::IAM::Role"
    Properties:
      AssumeRolePolicyDocument:
        Statement:
          - Action:
              - "sts:AssumeRole"
            Effect: Allow
            Principal:
              Service:
                - s3.amazonaws.com
  BucketBackupPolicy:
    Type: "AWS::IAM::Policy"
    Properties:
      PolicyDocument:
        Statement:
          - Action:
              - "s3:GetReplicationConfiguration"
              - "s3:ListBucket"
            Effect: Allow
            Resource:
              - "Fn::Join":
                  - ""
                  - - "arn:aws:s3:::"
                    - Ref: RecordServiceS3Bucket
          - Action:
              - "s3:GetObjectVersion"
              - "s3:GetObjectVersionAcl"
            Effect: Allow
            Resource:
              - "Fn::Join":
                  - ""
                  - - "arn:aws:s3:::"
                    - Ref: RecordServiceS3Bucket
                    - /*
          - Action:
              - "s3:ReplicateObject"
              - "s3:ReplicateDelete"
            Effect: Allow
            Resource:
              - "Fn::Join":
                  - ""
                  - - "arn:aws:s3:::"
                    - "Fn::Join":
                        - "-"
                        - - Ref: "AWS::Region"
                          - Ref: "AWS::StackName"
                          - replicationbucket
                    - /*
      PolicyName: BucketBackupPolicy
      Roles:
        - Ref: WorkItemBucketBackupRole

Positive test num. 2 - json file

{
  "Description": "A sample template",
  "Resources": {
    "WorkItemBucketBackupRole": {
      "Type": "AWS::IAM::Role",
      "Properties": {
        "AssumeRolePolicyDocument": {
          "Statement": [
            {
              "Action": [
                "sts:AssumeRole"
              ],
              "Effect": "Allow",
              "Principal": {
                "Service": [
                  "s3.amazonaws.com"
                ]
              }
            }
          ]
        }
      }
    },
    "BucketBackupPolicy": {
      "Type": "AWS::IAM::Policy",
      "Properties": {
        "PolicyDocument": {
          "Statement": [
            {
              "Resource": [
                {
                  "Fn::Join": [
                    "",
                    [
                      "arn:aws:s3:::",
                      {
                        "Ref": "RecordServiceS3Bucket"
                      }
                    ]
                  ]
                }
              ],
              "Action": [
                "s3:GetReplicationConfiguration",
                "s3:ListBucket"
              ],
              "Effect": "Allow"
            },
            {
              "Action": [
                "s3:GetObjectVersion",
                "s3:GetObjectVersionAcl"
              ],
              "Effect": "Allow",
              "Resource": [
                {
                  "Fn::Join": [
                    "",
                    [
                      "arn:aws:s3:::",
                      {
                        "Ref": "RecordServiceS3Bucket"
                      },
                      "/*"
                    ]
                  ]
                }
              ]
            },
            {
              "Action": [
                "s3:ReplicateObject",
                "s3:ReplicateDelete"
              ],
              "Effect": "Allow",
              "Resource": [
                {
                  "Fn::Join": [
                    "",
                    [
                      "arn:aws:s3:::",
                      {
                        "Fn::Join": [
                          "-",
                          [
                            {
                              "Ref": "AWS::Region"
                            },
                            {
                              "Ref": "AWS::StackName"
                            },
                            "replicationbucket"
                          ]
                        ]
                      },
                      "/*"
                    ]
                  ]
                }
              ]
            }
          ]
        },
        "PolicyName": "BucketBackupPolicy",
        "Roles": [
          {
            "Ref": "WorkItemBucketBackupRole"
          }
        ]
      }
    },
    "mybucket": {
      "Properties": {
        "ReplicationConfiguration": {
          "Role": {
            "Fn::GetAtt": [
              "WorkItemBucketBackupRole",
              "Arn"
            ]
          },
          "Rules": [
            {
              "Prefix": "",
              "Status": "Enabled",
              "Destination": {
                "Bucket": {
                  "Fn::Join": [
                    "",
                    [
                      "arn:aws:s3:::",
                      {
                        "Fn::Join": [
                          "-",
                          [
                            {
                              "Ref": "AWS::Region"
                            },
                            {
                              "Ref": "AWS::StackName"
                            },
                            "replicationbucket"
                          ]
                        ]
                      }
                    ]
                  ]
                },
                "StorageClass": "STANDARD"
              },
              "Id": "Backup"
            }
          ]
        },
        "VersioningConfiguration": {
          "Status": "Enabled"
        }
      },
      "Type": "AWS::S3::Bucket",
      "DeletionPolicy": "Retain"
    }
  },
  "AWSTemplateFormatVersion": "2010-09-09"
}

Code samples without security vulnerabilities

Negative test num. 1 - yaml file

AWSTemplateFormatVersion: "2010-09-09"
Description: A sample template
Resources:
  RecordServiceS3Bucket:
    Type: "AWS::S3::Bucket"
    DeletionPolicy: Retain
    Properties:
      ReplicationConfiguration:
        Role:
          "Fn::GetAtt":
            - WorkItemBucketBackupRole
            - Arn
        Rules:
          - Destination:
              Bucket:
                "Fn::Join":
                  - ""
                  - - "arn:aws:s3:::"
                    - "Fn::Join":
                        - "-"
                        - - Ref: "AWS::Region"
                          - Ref: "AWS::StackName"
                          - replicationbucket
              StorageClass: STANDARD
            Id: Backup
            Prefix: ""
            Status: Enabled
      VersioningConfiguration:
        Status: Enabled
      LoggingConfiguration:
        DestinationBucketName: !Ref LoggingBucket
        LogFilePrefix: loga/
  WorkItemBucketBackupRole:
    Type: "AWS::IAM::Role"
    Properties:
      AssumeRolePolicyDocument:
        Statement:
          - Action:
              - "sts:AssumeRole"
            Effect: Allow
            Principal:
              Service:
                - s3.amazonaws.com
  BucketBackupPolicy:
    Type: "AWS::IAM::Policy"
    Properties:
      PolicyDocument:
        Statement:
          - Action:
              - "s3:GetReplicationConfiguration"
              - "s3:ListBucket"
            Effect: Allow
            Resource:
              - "Fn::Join":
                  - ""
                  - - "arn:aws:s3:::"
                    - Ref: RecordServiceS3Bucket
          - Action:
              - "s3:GetObjectVersion"
              - "s3:GetObjectVersionAcl"
            Effect: Allow
            Resource:
              - "Fn::Join":
                  - ""
                  - - "arn:aws:s3:::"
                    - Ref: RecordServiceS3Bucket
                    - /*
          - Action:
              - "s3:ReplicateObject"
              - "s3:ReplicateDelete"
            Effect: Allow
            Resource:
              - "Fn::Join":
                  - ""
                  - - "arn:aws:s3:::"
                    - "Fn::Join":
                        - "-"
                        - - Ref: "AWS::Region"
                          - Ref: "AWS::StackName"
                          - replicationbucket
                    - /*
      PolicyName: BucketBackupPolicy
      Roles:
        - Ref: WorkItemBucketBackupRole

Negative test num. 2 - json file

{
  "Resources": {
    "RecordServiceS3Bucket": {
      "Properties": {
        "ReplicationConfiguration": {
          "Role": {
            "Fn::GetAtt": [
              "WorkItemBucketBackupRole",
              "Arn"
            ]
          },
          "Rules": [
            {
              "Status": "Enabled",
              "Destination": {
                "Bucket": {
                  "Fn::Join": [
                    "",
                    [
                      "arn:aws:s3:::",
                      {
                        "Fn::Join": [
                          "-",
                          [
                            {
                              "Ref": "AWS::Region"
                            },
                            {
                              "Ref": "AWS::StackName"
                            },
                            "replicationbucket"
                          ]
                        ]
                      }
                    ]
                  ]
                },
                "StorageClass": "STANDARD"
              },
              "Id": "Backup",
              "Prefix": ""
            }
          ]
        },
        "VersioningConfiguration": {
          "Status": "Enabled"
        },
        "LoggingConfiguration": {
          "DestinationBucketName": "LoggingBucket",
          "LogFilePrefix": "loga/"
        }
      },
      "Type": "AWS::S3::Bucket",
      "DeletionPolicy": "Retain"
    },
    "WorkItemBucketBackupRole": {
      "Type": "AWS::IAM::Role",
      "Properties": {
        "AssumeRolePolicyDocument": {
          "Statement": [
            {
              "Principal": {
                "Service": [
                  "s3.amazonaws.com"
                ]
              },
              "Action": [
                "sts:AssumeRole"
              ],
              "Effect": "Allow"
            }
          ]
        }
      }
    },
    "BucketBackupPolicy": {
      "Type": "AWS::IAM::Policy",
      "Properties": {
        "PolicyDocument": {
          "Statement": [
            {
              "Action": [
                "s3:GetReplicationConfiguration",
                "s3:ListBucket"
              ],
              "Effect": "Allow",
              "Resource": [
                {
                  "Fn::Join": [
                    "",
                    [
                      "arn:aws:s3:::",
                      {
                        "Ref": "RecordServiceS3Bucket"
                      }
                    ]
                  ]
                }
              ]
            },
            {
              "Action": [
                "s3:GetObjectVersion",
                "s3:GetObjectVersionAcl"
              ],
              "Effect": "Allow",
              "Resource": [
                {
                  "Fn::Join": [
                    "",
                    [
                      "arn:aws:s3:::",
                      {
                        "Ref": "RecordServiceS3Bucket"
                      },
                      "/*"
                    ]
                  ]
                }
              ]
            },
            {
              "Action": [
                "s3:ReplicateObject",
                "s3:ReplicateDelete"
              ],
              "Effect": "Allow",
              "Resource": [
                {
                  "Fn::Join": [
                    "",
                    [
                      "arn:aws:s3:::",
                      {
                        "Fn::Join": [
                          "-",
                          [
                            {
                              "Ref": "AWS::Region"
                            },
                            {
                              "Ref": "AWS::StackName"
                            },
                            "replicationbucket"
                          ]
                        ]
                      },
                      "/*"
                    ]
                  ]
                }
              ]
            }
          ]
        },
        "PolicyName": "BucketBackupPolicy",
        "Roles": [
          {
            "Ref": "WorkItemBucketBackupRole"
          }
        ]
      }
    }
  },
  "AWSTemplateFormatVersion": "2010-09-09",
  "Description": "A sample template"
}