If you’ve had discussions with a security organization recently, there’s a high probability that the word automation has come up. As organizations scale and consume the benefits the cloud has to offer, it’s important to factor in and understand how the additional cloud footprint will affect operations. Automation is a key enabler for efficient operations and can help drive down the number of repetitive tasks that the operational teams have to perform.
Alert fatigue is caused when humans work on the same repetitive tasks day in and day out and also have a large volume of alerts that need to be addressed. The repetitive nature of these tasks can cause analysts to become numb to the importance of the task or make errors due to manual processing. This can lead to misclassification of security alerts or higher-severity alerts being overlooked due to investigation times. Automation is key here to reduce the number of repetitive tasks and give analysts time to focus on other areas of importance.
In this blog post, we’ll walk you through new capabilities within AWS Security Hub that you can use to take automated actions to update findings. We’ll show you some example scenarios that use this capability and set you up with the knowledge you need to get started with creating automation rules.
Automation rules in Security Hub
AWS Security Hub is available globally and is designed to give you a comprehensive view of your security posture across your AWS accounts. With Security Hub, you have a single place that aggregates, organizes, and prioritizes your security alerts, or findings, from multiple AWS services, including Amazon GuardDuty, Amazon Inspector, Amazon Macie, AWS Firewall Manager, AWS Systems Manager Patch Manager, AWS Config, AWS Health, and AWS Identity and Access Management (IAM) Access Analyzer, as well as from over 65 AWS Partner Network (APN) solutions.
Previously, Security Hub could take automated actions on findings, but this involved going to the Amazon EventBridge console or API, creating an EventBridge rule, and then building an AWS Lambda function, an AWS Systems Manager Automation runbook, or an AWS Step Functions step as the target of that rule. If you wanted to set up these automated actions in the administrator account and home AWS Region and run them in member accounts and in linked Regions, you would also need to deploy the correct IAM permissions to enable the actions to run across accounts and Regions. After setting up the automation flow, you would need to maintain the EventBridge rule, Lambda function, and IAM roles. Such maintenance could include upgrading the Lambda versions, verifying operational efficiency, and checking that everything is running as expected.
With Security Hub, you can now use rules to automatically update various fields in findings that match defined criteria. This allows you to automatically suppress findings, update findings’ severities according to organizational policies, change findings’ workflow status, and add notes. As findings are ingested, automation rules look for findings that meet defined criteria and update the specified fields in findings that meet the criteria. For example, a user can create a rule that automatically sets the finding’s severity to “Critical” if the finding account ID is of a known business-critical account. A user could also automatically suppress findings for a specific control in an account where the finding represents an accepted risk.
With automation rules, Security Hub provides you a simplified way to build automations directly from the Security Hub console and API. This reduces repetitive work for cloud security and DevOps engineers and can reduce the mean time to response.
In this section, we’ve put together some examples of how Security Hub automation rules can help you. There’s a lot of flexibility in how you can use the rules, and we expect there will be many variations that your organization will use when contextual information about security risk has been added.
Scenario 1: Elevate finding severity for specific controls based on account IDs
Security Hub offers protection by using hundreds of security controls that create findings that have a severity associated with them. Sometimes, you might want to elevate that severity according to your organizational policies or according to the context of the finding, such as the account it relates to. With automation rules, you can now automatically elevate the severity for specific controls when they are in a specific account.
For example, the AWS Foundational Security Best Practices control GuardDuty.1 has a “High” severity by default. But you might consider such a finding to have “Critical” severity if it occurs in one of your top production accounts. To change the severity automatically, you can choose GeneratorId as a criteria and check that it’s equal to aws-foundational-security-best-practices/v/1.0.0/GuardDuty.1, and also add AwsAccountId as a criteria and check that it’s equal to YOUR_ACCOUNT_IDs. Then, add an action to update the severity to “Critical,” and add a note to the person who will look at the finding that reads “Urgent — look into these production accounts.”
You can set up this automation rule through the AWS CLI, the console, the Security Hub API, or the AWS SDK for Python (Boto3), as follows.
To set up the automation rule for Scenario 1 (AWS CLI)
In the AWS CLI, run the following command to create a new automation rule with a specific Amazon Resource Name (ARN). Note the different modifiable parameters:
Rule-name — The name of the rule that will be created.
Rule-status — An optional parameter. Specify whether you want Security Hub to activate and start applying the rule to findings after creation. If no value is specified, the default value is ENABLED. A value of DISABLED means that the rule will be paused after creation.
Rule-order — Provide the processing order for the rule. Security Hub applies rules with a lower numerical value for this parameter first.
Criteria — Provide the criteria that you want Security Hub to use to filter your findings. The rule action will be applied to findings that match the criteria. For a list of supported criteria, see Criteria and actions for automation rules. In this example, the criteria are placeholders and should be replaced.
Actions — Provide the actions that you want Security Hub to take when there’s a match between a finding and your defined criteria. For a list of supported actions, see Criteria and actions for automation rules. In this example, the actions are placeholders and should be replaced.
To set up the automation rule for Scenario 1 (console)
Open the Security Hub console, and in the left navigation pane, choose Automations.
Choose Create rule, and then choose Create a custom rule to get started with creating a rule of your choice. Add a rule name and description.
Under Criteria, add the following information.
Key = GeneratorID
Operator = EQUALS
Value = aws-foundational-security-best-practices/v/1.0.0/GuardDuty.1
Key = AwsAccountId
Operator = EQUALS
Value = Your AWS account ID
You can preview which findings will match the criteria by looking in the preview section.
Next, under Automated action, specify which finding value to update automatically when findings match your criteria.
For Rule status, choose Enabled, and then choose Create rule.
After you choose Create rule, you will see the newly created rule within the Automations portal.
Note: In figure 7, you can see multiple automation rules. When you create automation rules, you assign each rule an order number. This determines the order in which Security Hub applies your automation rules. This becomes important when multiple rules apply to the same finding or finding field. When multiple rule actions apply to the same finding field, the rule with the highest numerical value for rule order is applied last and has the ultimate effect on that field.
Additionally, if your preferred deployment method is to use the API or AWS SDK for Python (Boto3), we have information on how you can use these means of deployment in our public documentation.
Scenario 2: Change the finding severity to high if a resource is important, based on resource tags
Imagine a situation where you have findings associated to a wide range of resources. Typically, organizations will attempt to prioritize which findings to remediate first. You can achieve this prioritization through Security Hub and the contextual fields that are available for you to use — for example, by using the severity of the finding or the account ID the resource is sitting in. You might also have your own prioritization based on other factors. You could add this additional context to findings by using a tagging strategy. With automation rules, you can now automatically elevate the severity for specific findings based on the tag value associated to the resource.
For example, if a finding comes into Security Hub with the severity rating “Medium,” but the resource in question is critical to the business and has the tag production associated to it, you could automatically raise the severity rating to “High.”
Note: This will work only for findings where there is a resource tag associated with the finding.
Scenario 3: Suppress GuardDuty findings with a severity of “Informational”
GuardDuty provides an overarching view of the state of threats to deployed resources in your organization’s cloud environment. After evaluation, GuardDuty produces findings related to these threats. The findings produced by GuardDuty have different severities, to help organizations with prioritization. Some of these findings will be given an “Informational” severity. “Informational” indicates that no issue was found and the content of the finding is purely to give information. After you have evaluated the context of the finding, you might want to suppress any additional findings that match the same criteria.
For example, you might want to set up a rule so that new findings with the generator ID that produced “Informational” findings are suppressed, keeping only the findings that need action.
When you create a new rule, you can also choose to create a rule from a template. These templates are regularly updated with use cases that are applicable for many customers.
To set up an automation rule by using a template from the console
In the Security Hub console, choose Automations, and then choose Create rule.
Choose Create a rule from a template to get started with creating a rule of your choice.
Select a rule template from the drop-down menu.
(Optional) If necessary, modify the Rule, Criteria, and Automated action sections.
For Rule status, choose whether you want the rule to be enabled or disabled after it’s created.
(Optional) Expand the Additional settings section. Choose Ignore subsequent rules for findings that match these criteria if you want this rule to be the last rule applied to findings that match the rule criteria.
(Optional) For Tags, add tags as key-value pairs to help you identify the rule.
Choose Create rule.
For organizations that operate in multiple AWS Regions, we’ve provided a solution that you can use to replicate rules created in your central Security Hub admin account into these additional Regions. You can find the sample code for this solution in our GitHub repo.
In this blog post, we’ve discussed the importance of automation and its ability to help organizations scale operations within the cloud. We’ve introduced a new capability in AWS Security Hub, automation rules, that can help reduce the repetitive tasks your operational teams may be facing, and we’ve showcased some example use cases to get you started. Start using automation rules in your environment today. We’re excited to see what use cases you will solve with this feature and as always, are happy to receive any feedback.
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