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Event Information

  • The DescribeKey event in AWS for KMS (Key Management Service) is used to retrieve detailed information about a specific customer master key (CMK) in the AWS Key Management Service.
  • This event provides metadata about the key, such as its key ID, key ARN, creation date, key state, key usage, and key policy.
  • The DescribeKey event is useful for auditing and monitoring purposes, as it allows administrators to track and analyze the properties and configuration of their CMKs in AWS KMS.

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Examples

  • Unauthorized access to the KMS key: If security is impacted with DescribeKey in AWS for KMS, it could potentially allow unauthorized users to gain access to sensitive information stored within the key. This can lead to data breaches and compromise the confidentiality of the data.

  • Exposure of key metadata: The DescribeKey operation in AWS KMS provides detailed metadata about the key, including its key ID, creation date, and key state. If security is impacted, this information could be exposed to unauthorized users, potentially aiding them in their attempts to compromise the key or the data it protects.

  • Increased risk of key rotation attacks: If security is impacted with DescribeKey in AWS KMS, it could provide attackers with valuable information about the key rotation schedule. This information can be used to plan and execute attacks during key rotation events, potentially leading to unauthorized access to encrypted data.

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Remediation

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Using Console

  1. Identify the affected AWS KMS key:

    • Log in to the AWS Management Console.
    • Go to the AWS Key Management Service (KMS) console.
    • Navigate to the “Customer managed keys” section.
    • Look for the key mentioned in the previous response.

  2. Update key policy to restrict access:

    • Select the key from the list.
    • Click on the “Key policy” tab.
    • Review the existing key policy and identify the necessary changes based on the examples provided.
    • Click on the “Edit” button to modify the key policy.
    • Make the required changes to restrict access to the key.
    • Ensure that only authorized IAM users or roles have the necessary permissions.
    • Save the updated key policy.

  3. Monitor and review key usage:

    • Enable AWS CloudTrail to capture API calls related to the KMS key.
    • Set up CloudWatch alarms to notify you of any suspicious or unauthorized key usage.
    • Regularly review the CloudTrail logs and CloudWatch alarms to detect any potential security issues.
    • Take appropriate actions if any unauthorized access or suspicious activity is identified, such as rotating the key or revoking access.

Note: The above steps are general guidelines and may vary based on your specific requirements and the AWS console interface. Always refer to the official AWS documentation for detailed instructions.

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Using CLI

To remediate issues related to AWS Key Management Service (KMS) using AWS CLI, you can follow these steps:

  1. Rotate KMS keys:

    • Identify the KMS key(s) that need to be rotated.
    • Generate a new key using the create-key command: aws kms create-key.
    • Update the necessary resources to use the new key.
    • Schedule the deletion of the old key using the schedule-key-deletion command: aws kms schedule-key-deletion --key-id <old-key-id> --pending-window-in-days <number-of-days>.
    • Monitor the key rotation process and ensure that all resources are successfully using the new key.

  2. Enable KMS key rotation:

    • Check if key rotation is already enabled for a specific KMS key using the get-key-rotation-status command: aws kms get-key-rotation-status --key-id <key-id>.
    • If key rotation is not enabled, enable it using the enable-key-rotation command: aws kms enable-key-rotation --key-id <key-id>.

  3. Monitor KMS key usage:

    • Enable CloudTrail logging for KMS API calls to monitor key usage and detect any suspicious activities.
    • Use the list-key-aliases command to list all key aliases: aws kms list-key-aliases.
    • Review the key usage patterns and access policies regularly to ensure compliance with security best practices.

Please note that the commands provided are examples and may need to be modified based on your specific requirements and environment.

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Using Python

To remediate the issues related to AWS KMS using Python, you can follow these steps:

  1. Enable AWS CloudTrail for KMS:

    • Use the boto3 library to create a new CloudTrail trail for KMS.
    • Set the appropriate parameters such as the S3 bucket to store the logs and the KMS key to encrypt the logs.
    • Enable logging for KMS API calls by specifying the kms.amazonaws.com as the resource type.
    • Here’s an example Python script:
    import boto3

def enable_kms_cloudtrail():
    client = boto3.client('cloudtrail')
    response = client.create_trail(
        Name='kms-cloudtrail',
        S3BucketName='your-s3-bucket',
        KmsKeyId='your-kms-key-id',
        IsMultiRegionTrail=True,
        IncludeGlobalServiceEvents=True,
        EnableLogFileValidation=True,
        IsOrganizationTrail=False,
        Tags=[
            {
                'Key': 'Name',
                'Value': 'kms-cloudtrail'
            },
        ]
    )
    client.start_logging(Name='kms-cloudtrail')

enable_kms_cloudtrail()

  2. Enable AWS Config for KMS:

    • Use the boto3 library to create a new AWS Config rule for KMS.
    • Specify the rule parameters such as the KMS key usage and key rotation settings.
    • Here’s an example Python script:
    import boto3

def enable_kms_config():
    client = boto3.client('config')
    response = client.put_config_rule(
        ConfigRule={
            'ConfigRuleName': 'kms-config-rule',
            'Description': 'KMS Config Rule',
            'Scope': {
                'ComplianceResourceTypes': [
                    'AWS::KMS::Key'
                ]
            },
            'Source': {
                'Owner': 'AWS',
                'SourceIdentifier': 'KMS_KEY_ROTATION_ENABLED'
            },
            'InputParameters': '{"kmsKeyRotationEnabled": "true"}',
            'ConfigRuleState': 'ACTIVE'
        }
    )

enable_kms_config()

  3. Enable AWS Security Hub for KMS:

    • Use the boto3 library to enable AWS Security Hub for KMS.
    • Specify the KMS key as a resource and enable the relevant security standards.
    • Here’s an example Python script:
    import boto3

def enable_kms_security_hub():
    client = boto3.client('securityhub')
    response = client.batch_enable_standards(
        StandardsSubscriptionRequests=[
            {
                'StandardsArn': 'arn:aws:securityhub:::ruleset/cis-aws-foundations-benchmark/v/1.2.0',
                'StandardsInput': '{"keyArn": "your-kms-key-arn"}'
            }
        ]
    )

enable_kms_security_hub()

Please note that you need to have the necessary IAM permissions to perform these actions. Make sure to replace the placeholders with your own values before executing the scripts.