metadata:
  id: 3ed0b9d8-c5f2-55e2-92a5-2531868e79ca
  name: Ensure that Object-level logging for write events is enabled for S3 bucket
  profile_applicability: '* Level 2'
  description: |-
    S3 object-level API operations such as GetObject, DeleteObject, and PutObject are called data events.
    By default, CloudTrail trails don't log data events and so it is recommended to enable Object-level logging for S3 buckets.
  rationale: |-
    Enabling object-level logging will help you meet data compliance requirements within your organization, perform comprehensive security analysis, monitor specific patterns of user behavior in your AWS account or take immediate actions on any object-level API activity within your S3 Buckets using Amazon CloudWatch Events.
  audit: |-
    **From Console:**

    1. Login to the AWS Management Console and navigate to CloudTrail dashboard at `https://console.aws.amazon.com/cloudtrail/`
    2. In the left panel, click `Trails` and then click on the CloudTrail Name that you want to examine.
    3. Review `General details`
    4. Confirm that `Multi-region trail` is set to `Yes`
    5. Scroll down to `Data events`
    6. Confirm that it reads:
    Data events: S3
    Bucket Name: All current and future S3 buckets
    Read: Enabled
    Write: Enabled
    7. Repeat steps 2 to 6 to verify that Multi-region trail and Data events logging of S3 buckets in CloudTrail.
    If the CloudTrails do not have multi-region and data events configured for S3 refer to the remediation below.

    **From Command Line:**

    8. Run `list-trails` command to list the names of all Amazon CloudTrail trails currently available in all AWS regions:
    ```
    aws cloudtrail list-trails
    ```
    9. The command output will be a list of all the trail names to include.
    "TrailARN": "arn:aws:cloudtrail:<region>:<account#>:trail/<trailname>",
    "Name": "<trailname>",
    "HomeRegion": "<region>"
    10. Next run 'get-trail- command to determine Multi-region.
    ```
    aws cloudtrail get-trail --name <trailname> --region <region_name>
    ```
    11. The command output should include:
    "IsMultiRegionTrail": true,
    12. Next run `get-event-selectors` command using the `Name` of the trail and the `region` returned in step 2 to determine if Data events logging feature is enabled within the selected CloudTrail trail for all S3 buckets:
    ```
    aws cloudtrail get-event-selectors --region <HomeRegion> --trail-name <trailname> --query EventSelectors[*].DataResources[]
    ```
    13. The command output should be an array that contains the configuration of the AWS resource(S3 bucket) defined for the Data events selector.
    "Type": "AWS::S3::Object",
     "Values": [
     "arn:aws:s3"
    14. If the `get-event-selectors` command returns an empty array '[]', the Data events are not included in the selected AWS Cloudtrail trail logging configuration, therefore the S3 object-level API operations performed within your AWS account are not recorded.
    15. Repeat steps 1 to 5 for auditing each CloudTrail to determine if Data events for S3 are covered.
    If Multi-region is not set to true and the Data events does not show S3 defined as shown refer to the remediation procedure below.
  remediation: |-
    **From Console:**

    1. Login to the AWS Management Console and navigate to S3 dashboard at `https://console.aws.amazon.com/s3/`
    2. In the left navigation panel, click `buckets` and then click on the S3 Bucket Name that you want to examine.
    3. Click `Properties` tab to see in detail bucket configuration.
    4. Click on the `Object-level` logging setting, enter the CloudTrail name for the recording activity. You can choose an existing Cloudtrail or create a new one by navigating to the Cloudtrail console link `https://console.aws.amazon.com/cloudtrail/`
    5. Once the Cloudtrail is selected, check the `Write` event checkbox, so that `object-level` logging for Write events is enabled.
    6. Repeat steps 2 to 5 to enable object-level logging of write events for other S3 buckets.

    **From Command Line:**

    7. To enable `object-level` data events logging for S3 buckets within your AWS account, run `put-event-selectors` command using the name of the trail that you want to reconfigure as identifier:
    ```
    aws cloudtrail put-event-selectors --region <region-name> --trail-name <trail-name> --event-selectors '[{
        "ReadWriteType": "WriteOnly",
        "IncludeManagementEvents": true,
        "DataResources": [
            {
                "Type": "AWS::S3::Object",
                "Values": [
                    "arn:aws:s3:::<s3-bucket-name>/"
                ]
            }
        ]
    }]'
    ```
    8. The command output will be `object-level` event trail configuration.
    9. If you want to enable it for all buckets at once then change Values parameter to `["arn:aws:s3"]` in command given above.
    10. Repeat step 1 for each s3 bucket to update `object-level` logging of write events.
    11. Change the AWS region by updating the `--region` command parameter and perform the process for other regions.
  impact: ''
  default_value: ''
  references: 1. 
    https://docs.aws.amazon.com/AmazonS3/latest/user-guide/enable-cloudtrail-events.html
  section: Logging
  version: '1.0'
  tags:
  - CIS
  - AWS
  - CIS 3.10
  - Logging
  benchmark:
    name: CIS Amazon Web Services Foundations
    version: v1.5.0
    id: cis_aws
    rule_number: '3.10'
    posture_type: cspm
