AWS Security Blog

Nine AWS Security Hub best practices

AWS Security Hub is a security and compliance service that became generally available on June 25, 2019. It provides you with extensive visibility into your security and compliance status across multiple AWS accounts, in a single dashboard per region. The service helps you monitor critical settings to ensure that your AWS accounts remain secure, allowing you to notice and react quickly to any changes in your environment.

AWS Security Hub aggregates, organizes, and prioritizes security findings from supported AWS services—that’s Amazon GuardDuty, Amazon Inspector, and Amazon Macie at the time this post was published—and from various AWS partner security solutions. AWS Security Hub also generates its own findings, based on automated, resource-level and account-level configuration and compliance checks using service-linked AWS Config rules plus other analytic techniques. These checks help you keep your AWS accounts compliant with industry standards and best practices, such as the Center for Internet Security (CIS) AWS Foundations standard.

In this post, I’ll provide nine best practices to help you use AWS Security Hub as effectively as possible.

1. Use the AWS Labs script to turn on Security Hub in all your AWS accounts in all regions and to establish your existing Amazon GuardDuty master/member hierarchy

As a best practice, you should continuously monitor all regions across all of your AWS accounts for unauthorized behavior or misconfigurations, even in regions that you don’t use heavily. AWS already recommends that you do this when using monitoring services like AWS Config and AWS CloudTrail. I recommend that you enable Security Hub in every region available in your AWS accounts.

In addition, you can also invite other AWS accounts to enable Security Hub and share findings with your AWS account. If you send an invitation and it is accepted by the other account owner, your Security Hub account is designated as the master account, and any associated Security Hub accounts become your member accounts. Users from the master account will then be able to view Security Hub findings from member accounts.

To simplify these configurations, you can utilize the AWS Labs script available on GitHub, which provides a step-by-step guide to automate this process. This script allows you to enable (and disable) AWS Security Hub simultaneously across a list of associated AWS accounts and bulk-add them to become your Security Hub members; it sends invitations from the master account and automatically accepts invitations in all member accounts. To run the script, you must have the AWS account IDs and root email addresses of the AWS accounts that you want as your Security Hub members. (Note that you should only share your root email address and account ID with AWS accounts that you trust. Visit the IAM best practices page to learn more about how to keep access to your AWS accounts secured.)

By default, the Security Hub master/member association is independent of the relationships that you’ve established between your Amazon GuardDuty or Amazon Macie accounts and other associated accounts. If you have an existing master/member hierarchy in GuardDuty or Macie, you can export that list of accounts into a CSV file and then use it with the script. For example in GuardDuty, use the ListMembers API to export the AWS Account ID and email of all member accounts, as follows:

aws guardduty list-members --detector-id <Detector ID> --query "Members[].[AccountId, Email]" --output text | awk '{print $1 "," $2}'

The output of the above command will be your GuardDuty member account IDs and their corresponding root email addresses, one per line and separated with a comma as shown below:

12345678910,abc@example.com
98765432101,xyz@example.com

2. Enable AWS Config in all AWS accounts and regions and leave the AWS CIS Foundations standard check enabled

When you enable Security Hub in any region, the AWS CIS standard checks are enabled by default. I recommend leaving them enabled; they are important security measures that are applicable to all AWS accounts.

To run most of these checks, Security Hub uses service-linked AWS Config rules. Because of this, you should make sure that AWS Config is turned on and recording all supported resources, including global resources, in all accounts and regions where Security Hub is deployed. You are not charged by AWS Config for these service-linked rules. You are only charged via Security Hub’s pricing model.

3. Use specific managed IAM policies for different types of Security Hub users

You can choose to allow a large group of users to access List and Read Security Hub actions, which will permit them to view your security findings. However, you should allow only a small group of users to access the Security Hub Write actions. This will permit only authorized users to archive, resolve, or remediate the findings.

You can use AWS managed policies to give your employees the permissions they need to get started. These policies are already available in your account and are maintained and updated by AWS. To grant more granular permission to your Security Hub users, I recommend that you create your own customer managed policies. A great place to start with this is to import an existing AWS managed policy. That way, you know that the policy is initially correct, and all you need to do is customize it for your environment.

AWS categorizes each service action into one of five access levels based on what each action does: List, Read, Write, Permissions management, or Tagging. To determine which access level to include in the IAM policies that you assign to your users, you can view the policy summary by navigating from the IAM Console to Policies, then selecting any AWS managed or customer managed policy. Next, on the Summary page, under the Permissions tab, select Policy summary (see Figure 1). For more details and examples of access level classification, see Understanding Access Level Summaries Within Policy Summaries.
 

Figure 1: Policy summary of AWSSecurityHubReadOnlyAccess AWS managed policy

Figure 1: Policy summary of AWSSecurityHubReadOnlyAccess AWS managed policy

4. Use tags for access controls and cost allocation

A SecurityHub::Hub resource represents the implementation of the AWS Security Hub service per region in your AWS account. Security Hub allows you to assign metadata to your SecurityHub::Hub resource in the form of tags. Each tag is a string consisting of a user-defined key and an optional key-value that makes it easier for you to identify and manage the AWS resources in your environment.

You can control access permissions by using tags on your SecurityHub::Hub resource. For example, you can allow a group of developer IAM entities to manage and update only the SecurityHub::Hub resources that have the tag key developer associated with them. This can help you restrict access to your production SecurityHub::Hub resources, while allowing your developers to continue testing in their developer environment.

For more information on the supported tag-based conditions which you can use with the Security Hub APIs, refer to Condition Keys for AWS Security Hub. Please note that when you use tag-based conditions for access control, you must define who can modify those tags.

To make it easier to categorize and track your AWS costs, you can also activate cost allocation tags. This helps you organize your SecurityHub::Hub resource costs. AWS generates a cost allocation report as a CSV file, with your usage and costs grouped according to your active tags. You can apply tags that represent business categories (such as cost centers, application names, or project environments) to organize your costs.

For more information on commonly used tagging categories and effective tagging strategies, read about AWS Tagging Strategies.

5. Integrate and enable your existing security products (with 34 integrations today and more to come)

Numerous tools can help you understand the security and compliance posture of your AWS accounts, but these tools generate their own set of findings, often in different formats. Security Hub normalizes the findings.

With Security Hub, findings generated from integrated providers (both third-party services and AWS services) are ingested using a standard findings format, which eliminates the need for security teams to convert the data. You can currently integrate 34 findings providers to import and/or export findings with Security Hub. Some partner products, like PagerDuty, Splunk, and Slack, can receive findings from Security Hub, although they don’t generate findings.

If you want to add a third-party partner product to your AWS environment, you can choose the Purchase link from the Security Hub console’s Integrations page and navigate to AWS Marketplace. Once purchased, choose the Configure link to navigate to step-by-step instructions to install the product and configure its integration with Security Hub. Then choose Enable integration to create a product subscription in your account for that third-party provider (see Figure 2).

After you enable a subscription, a resource policy is automatically attached to it. The resource policy defines the permissions that Security Hub needs to accept and process the product’s findings. You can also enable the subscription via the API and CloudFormation.
 

Figure 2: Integrating partner findings provider with Security Hub

Figure 2: Integrating partner findings provider with Security Hub

6. Build out customized remediation playbooks using Amazon CloudWatch Events, AWS Systems Manager Automation documents, and AWS Step Functions to automatically resolve findings that don’t require human intervention

Security Hub automatically sends all findings to Amazon CloudWatch Events. This integration helps you automate your response to threat incidents by allowing you to take specific actions using AWS Systems Manager Automation documents, OpsItems, and AWS Step Functions. Using these tools, you can create your own incident handling plan. This will allow your security team to focus on strengthening the security of your AWS environments rather than on remediating the current findings.
 

Figure 3: Creating a CloudWatch Events Rule for sending matched Security Hub findings to specific Targets

Figure 3: Creating a CloudWatch Events Rule for sending matched Security Hub findings to specific Targets

7. Create custom actions to send a copy of a Security Hub finding to a resource that is internal or external to your AWS account, enabling additional visibility and remediation options for the finding

Because of its integration with CloudWatch Events, you can use Security Hub to create custom actions that will send specific findings to ticketing, chat, email, or automated remediation systems. Custom actions can also be sent to your own AWS resources, such as AWS Systems Manager OpsCenter, AWS Lambda or Amazon Kinesis, allowing you to do your own remediation or data capture related to the finding.

For an in-depth look at this architecture, plus specific examples of how to implement custom actions, see How to Integrate AWS Security Hub Custom Actions with PagerDuty and How to Enable Custom Actions in AWS Security Hub.

In addition, Security Hub gives you the option to choose a language-specific AWS SDK so that you can use custom actions to resolve findings programmatically. Below, I’ll demonstrate how you can implement this using AWS Lambda and AWS SDK for Python (Boto3). In my example, I’ll remediate the finding generated by Security Hub for CIS check 2.4, “Ensure CloudTrail trails are integrated with Amazon CloudWatch Logs.” For this walk-through, I assume that you have the necessary AWS IAM permissions to work with Security Hub, CloudWatch Events, Lambda and AWS CloudTrail.
 

Figure 4: Data flow supporting remediation of Security Hub findings using custom actions

Figure 4: Data flow supporting remediation of Security Hub findings using custom actions

As shown in figure 4:

  1. When findings against CIS check 2.4 are generated in Security Hub, Security Hub will send them to CloudWatch Events using custom actions that I’ll describe below.
  2. CloudWatch Events will send the findings to a Lambda function that has been configured as the target.
  3. The Lambda function will utilize a Python script to check whether the finding has been generated against CIS check 2.4. If it has, the Lambda function will identify the affected CloudTrail trail and configure it with CloudWatch Logs to monitor the trail logs.

Prerequisites

  1. You must configure an IAM Role for AWS CloudTrail to assume so that it can deliver events to your CloudWatch Logs log group. For more information about how to do this, refer to the AWS CloudTrail documentation. I’ll refer to this role as the CloudTrail role.
  2. To deploy the Lambda function, you must configure an IAM Role for the Lambda function to assume. I’ll refer to this role as the Lambda execution role. The following sample policy includes the permissions that you’ll assign to it for this example. Please replace <CloudTrail_CloudWatchLogs_Role> with the CloudTrail role that you created in the previous step. Depending on your use case, you can restrict this IAM policy further to grant least privilege, which is a recommended IAM Best Practice.

{
    "Version": "2012-10-17",
    "Statement": [
        {
            "Effect": "Allow",
            "Action": [
                "logs:CreateLogGroup",
                "logs:CreateLogStream",
                "logs:PutLogEvents",
                "logs:DescribeLogGroups",
                "cloudtrail:UpdateTrail",
                "iam:GetRole"
            ],
            "Resource": "*"
        },
        {
            "Effect": "Allow",
            "Action": "iam:PassRole",
            "Resource": "arn:aws:iam::012345678910:role/<CloudTrail_CloudWatchLogs_Role>"
        }
    ]
}     

Solution deployment

  1. Create a custom action in AWS Security Hub and associate it with a CloudWatch Events rule that you configure for your Security Hub findings. Follow the instructions laid out in the Security Hub user guide for the exact steps to do this.
  2. Create a Lambda Function, which will complete the auto-remediation of the CIS 2.4 findings:
    1. Open the Lambda Console and select Create function.
    2. On the next page, choose Author from scratch.
    3. Under Basic information, enter a name for your function. For Runtime, select Python 3.7.
       
      Figure 5: Updating basic information to create the Lambda function

      Figure 5: Updating basic information to create the Lambda function

    4. Under Permissions, expand Choose or create an execution role.
    5. Under Execution role, select the drop down menu and change the setting to Use an existing role.
    6. Under Existing role, select the Lambda execution role that you created earlier, then select Create function.
       
      Figure 6: Updating basic information and permissions to create the Lambda function

      Figure 6: Updating basic information and permissions to create the Lambda function

    7. Delete the default function code and paste the code I’ve provided below:
      
              import json, boto3
              cloudtrail_client = boto3.client('cloudtrail')
              cloudwatchlogs_client = boto3.client('logs')
              iam_client = boto3.client('iam')
              
              role_details = iam_client.get_role(RoleName='<CloudTrail_CloudWatchLogs_Role>')
              
              def lambda_handler(event, context):
                  # First off all, let us see if the JSON sent by CWE has any Security Hub findings.
                  if 'detail' in event.keys() and 'findings' in event['detail'].keys() and len(event['detail']['findings']) > 0:
                      print("There are some findings. Let's check them!")
                      print("Number of findings: %i" % len(event['detail']['findings']))
              
                      # Then we need to filter out the findings. In this code snippet, we'll handle only findings related to CloudTrail trails for integration with CloudWatch Logs.
                      for finding in event['detail']['findings']:
                          if 'Title' in finding.keys():
                              if 'Ensure CloudTrail trails are integrated with CloudWatch Logs' in finding['Title']:
                                  print("There's a CloudTrail-related finding. I can handle it!")
              
                                  if 'Compliance' in finding.keys() and 'Status' in finding['Compliance'].keys():
                                      print("Compliance Status: %s" % finding['Compliance']['Status'])
              
                                      # We can skip compliant findings, and evaluate only the non-compliant ones.                        
                                      if finding['Compliance']['Status'] == 'PASSED':
                                          continue
              
                                      # For each non-compliant finding, we need to get specific pieces of information so as to create the correct log group and update the CloudTrail trail.                        
                                      for resource in finding['Resources']:
                                          resource_id = resource['Id']
                                          cloudtrail_name = resource['Details']['Other']['name']
                                          loggroup_name = 'CloudTrail/' + cloudtrail_name
                                          print("ResourceId for the finding is %s" % resource_id)
                                          print("LogGroup name: %s" % loggroup_name)
              
                                          # At this point, we can create the log group using the name extracted from the finding.
                                          try:
                                              response_logs = cloudwatchlogs_client.create_log_group(logGroupName=loggroup_name)
                                          except Exception as e:
                                              print("Exception: %s" % str(e))
              
                                          # For updating the CloudTrail trail, we need to have the ARN of the log group. Let's retrieve it now.                            
                                          response_logsARN = cloudwatchlogs_client.describe_log_groups(logGroupNamePrefix = loggroup_name)
                                          print("LogGroup ARN: %s" % response_logsARN['logGroups'][0]['arn'])
                                          print("The role used by CloudTrail is: %s" % role_details['Role']['Arn'])
              
                                          # Finally, let's update the CloudTrail trail so that it sends logs to the new log group created.
                                          try:
                                              response_cloudtrail = cloudtrail_client.update_trail(
                                                  Name=cloudtrail_name,
                                                  CloudWatchLogsLogGroupArn = response_logsARN['logGroups'][0]['arn'],
                                                  CloudWatchLogsRoleArn = role_details['Role']['Arn']
                                              )
                                          except Exception as e:
                                              print("Exception: %s" % str(e))
                              else:
                                  print("Title: %s" % finding['Title'])
                                  print("This type of finding cannot be handled by this function. Skipping it…")
                          else:
                              print("This finding doesn't have a title and so cannot be handled by this function. Skipping it…")
                  else:
                      print("There are no findings to remediate.")            
              
    8. After pasting the code, replace <CloudTrail_CloudWatchLogs_Role> with your CloudTrail role and select Save to save your Lambda function.
       
      Figure 7: Editing Lambda code to replace the correct CloudTrail role

      Figure 7: Editing Lambda code to replace the correct CloudTrail role

  3. Go to your CloudWatch console and select Rules in the navigation pane on the left.
    1. From the list of CloudWatch rules that you see, select the rule which you created in Step 1 of this solution deployment.
    2. Then, select Actions on the top right of the page and choose Edit.
    3. On the Step 1: Create rule page, under Targets, choose Lambda function and select the Lambda function you created in Step 2.
    4. Select Configure details.
    5. On the Step 2: Configure rule details page, select Update rule.
       
      Figure 8: Adding your created Lambda function as Target for the CloudWatch rule

      Figure 8: Adding your created Lambda function as target for the CloudWatch rule

  4. Configuration is now complete, and you can test your rule. Go to your AWS Security Hub console and select Compliance standards in the navigation pane.
    1. Next, select CIS AWS Foundations.
       
      Figure 9: Compliance standards page in the Security Hub console

      Figure 9: Compliance standards page in the Security Hub console

    2. Search for the rule 2.4 Ensure CloudTrail trails are integrated with CloudWatch Logs and select it.
       
      Figure 10: Locating CIS check 2.4 in the Security Hub console

      Figure 10: Locating CIS check 2.4 in the Security Hub console

    3. If you’ve left the default AWS Security Hub CIS checks enabled (along with AWS Config service in the same region), and if you have CloudTrail trails in that region which are not yet configured to deliver events to CloudWatch Logs, you should see a low severity finding with a Failed Compliance status.
    4. Select the failed finding by selecting the checkbox and choosing the Actions button.
    5. Finally, from the dropdown menu, select the custom action that you created in Step 1 to send the finding to CloudWatch Events. CloudWatch Events will send the finding to your Lambda function, which you configured as the target for the rule in step 3. The Lambda function will automatically identify the affected CloudTrail trail and configure CloudWatch Logs log group for you. The log group will have the same name as your trail for identification purposes. You can modify the code to suit your needs further.

    Note: There may be a delay before the compliance status of the remediated resource changes. Once the CIS AWS Foundations Standard is enabled, Security Hub will run the checks within 2 hours. After that, the checks are automatically run once every 24 hours.

     

    Figure 11: Findings generated against CIS check 2.4 in the Security Hub Console

    Figure 11: Findings generated against CIS check 2.4 in the Security Hub console

    8. Customize your insights using the default “managed insights” as templates and use them to prioritize resources and findings to act upon

    A Security Hub “insight” is a collection of related findings to which one or more Security Hub filters have been applied. Insights can help you organize your findings and identify security risks that need immediate attention.

    Security Hub offers several managed (default) insights. You can use these as templates for new insights, and modify them depending on your use case. You can save these modified queries as new custom insights to ensure an even greater visibility of your AWS accounts. Please refer to the documentation for step-by-step instructions on how to create custom insights.
     

    Figure 12: Creating a Security Hub custom insight

    Figure 12: Creating a Security Hub custom insight

    9. Use the free trial to evaluate what your costs could be

    Security Hub provides a 30-day free trial for all AWS accounts and regions. The trial is a good way to evaluate how much Security Hub will cost, on average, to monitor threats and compliance in your environments. You can view an estimate by navigating from the Security Hub console to Settings, then Usage (see Figure 13).
     

    Figure 13: Estimating your Security Hub costs

    Figure 13: Estimating your Security Hub costs

    Conclusion

    AWS Security Hub allows you to have more visibility into the security and compliance status of your AWS environments. Using the Security Hub best practices discussed here, security teams can spend more time on incident remediation and recovery rather than incident detection and organization. Security Hub has undergone HIPAA, ISO, PCI, and SOC certification. To learn more about Security Hub, refer to the AWS Security Hub documentation.

    If you have comments about this post, submit them in the Comments section below. If you have questions about anything in this post, start a new thread on the AWS Security Hub forum or contact AWS Support.

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    Author

    Ketan Srivastava

    Ketan is a Cloud Support Engineer at AWS. He enjoys the fact that, at AWS, there are always so many opportunities to build things better for our customers and learn from these opportunities. Outside of work, he plays MOBAs and travels to new places with his wife. He holds a Master of Science degree from Rochester Institute of Technology.