Automate incident handling in Microsoft Sentinel with automation rules
Azure Sentinel is now called Microsoft Sentinel, and we’ll be updating these pages in the coming weeks. Learn more about recent Microsoft security enhancements.
This article explains what Microsoft Sentinel automation rules are, and how to use them to implement your Security Orchestration, Automation and Response (SOAR) operations, increasing your SOC's effectiveness and saving you time and resources.
What are automation rules?
Automation rules are a way to centrally manage the automation of incident handling, allowing you to perform simple automation tasks without using playbooks. For example, automation rules allow you to automatically assign incidents to the proper personnel, tag incidents to classify them, and change the status of incidents and close them. Automation rules can also automate responses for multiple analytics rules at once, control the order of actions that are executed, and run playbooks for those cases where more complex automation tasks are necessary. In short, automation rules streamline the use of automation in Microsoft Sentinel, enabling you to simplify complex workflows for your incident orchestration processes.
Automation rules are made up of several components:
Automation rules are triggered by the creation of an incident.
To review – incidents are created from alerts by analytics rules, of which there are several types, as explained in the tutorial Detect threats with built-in analytics rules in Microsoft Sentinel.
Complex sets of conditions can be defined to govern when actions (see below) should run. These conditions are typically based on the states or values of attributes of incidents and their entities, and they can include
Actions can be defined to run when the conditions (see above) are met. You can define many actions in a rule, and you can choose the order in which they’ll run (see below). The following actions can be defined using automation rules, without the need for the advanced functionality of a playbook:
Changing the status of an incident, keeping your workflow up to date.
Changing the severity of an incident – you can reevaluate and reprioritize based on the presence, absence, values, or attributes of entities involved in the incident.
Assigning an incident to an owner – this helps you direct types of incidents to the personnel best suited to deal with them, or to the most available personnel.
Adding a tag to an incident – this is useful for classifying incidents by subject, by attacker, or by any other common denominator.
Also, you can define an action to run a playbook, in order to take more complex response actions, including any that involve external systems. Only playbooks activated by the incident trigger are available to be used in automation rules. You can define an action to include multiple playbooks, or combinations of playbooks and other actions, and the order in which they will run.
Playbooks using either version of Logic Apps (Standard or Consumption) will be available to run from automation rules.
You can define an expiration date on an automation rule. The rule will be disabled after that date. This is useful for handling (that is, closing) "noise" incidents caused by planned, time-limited activities such as penetration testing.
You can define the order in which automation rules will run. Later automation rules will evaluate the conditions of the incident according to its state after being acted on by previous automation rules.
For example, if "First Automation Rule" changed an incident's severity from Medium to Low, and "Second Automation Rule" is defined to run only on incidents with Medium or higher severity, it won't run on that incident.
Common use cases and scenarios
Until now, only alerts could trigger an automated response, through the use of playbooks. With automation rules, incidents can now trigger automated response chains, which can include new incident-triggered playbooks (special permissions are required), when an incident is created.
Trigger playbooks for Microsoft providers
Automation rules provide a way to automate the handling of Microsoft security alerts by applying these rules to incidents created from the alerts. The automation rules can call playbooks (special permissions are required) and pass the incidents to them with all their details, including alerts and entities. In general, Microsoft Sentinel best practices dictate using the incidents queue as the focal point of security operations.
Microsoft security alerts include the following:
- Microsoft Defender for Cloud Apps
- Azure AD Identity Protection
- Microsoft Defender for Cloud
- Defender for IoT (formerly Azure Security Center for IoT)
- Microsoft Defender for Office 365 (formerly Office 365 ATP)
- Microsoft Defender for Endpoint (formerly MDATP)
- Microsoft Defender for Identity (formerly Azure ATP)
Multiple sequenced playbooks/actions in a single rule
You can now have near-complete control over the order of execution of actions and playbooks in a single automation rule. You also control the order of execution of the automation rules themselves. This allows you to greatly simplify your playbooks, reducing them to a single task or a small, straightforward sequence of tasks, and combine these small playbooks in different combinations in different automation rules.
Assign one playbook to multiple analytics rules at once
If you have a task you want to automate on all your analytics rules – say, the creation of a support ticket in an external ticketing system – you can apply a single playbook to any or all of your analytics rules – including any future rules – in one shot. This makes simple but repetitive maintenance and housekeeping tasks a lot less of a chore.
Automatic assignment of incidents
You can assign incidents to the right owner automatically. If your SOC has an analyst who specializes in a particular platform, any incidents relating to that platform can be automatically assigned to that analyst.
You can use rules to automatically resolve incidents that are known false/benign positives without the use of playbooks. For example, when running penetration tests, doing scheduled maintenance or upgrades, or testing automation procedures, many false-positive incidents may be created that the SOC wants to ignore. A time-limited automation rule can automatically close these incidents as they are created, while tagging them with a descriptor of the cause of their generation.
You can add expiration dates for your automation rules. There may be cases other than incident suppression that warrant time-limited automation. You may want to assign a particular type of incident to a particular user (say, an intern or a consultant) for a specific time frame. If the time frame is known in advance, you can effectively cause the rule to be disabled at the end of its relevancy, without having to remember to do so.
Automatically tag incidents
You can automatically add free-text tags to incidents to group or classify them according to any criteria of your choosing.
Automation rules execution
Automation rules are run sequentially, according to the order you determine. Each automation rule is executed after the previous one has finished its run. Within an automation rule, all actions are run sequentially in the order in which they are defined.
Playbook actions within an automation rule may be treated differently under some circumstances, according to the following criteria:
|Playbook run time||Automation rule advances to the next action...|
|Less than a second||Immediately after playbook is completed|
|Less than two minutes||Up to two minutes after playbook began running,
but no more than 10 seconds after the playbook is completed
|More than two minutes||Two minutes after playbook began running,
regardless of whether or not it was completed
Permissions for automation rules to run playbooks
When a Microsoft Sentinel automation rule runs a playbook, it uses a special Microsoft Sentinel service account specifically authorized for this action. The use of this account (as opposed to your user account) increases the security level of the service.
In order for an automation rule to run a playbook, this account must be granted explicit permissions to the resource group where the playbook resides. At that point, any automation rule will be able to run any playbook in that resource group.
When you're configuring an automation rule and adding a run playbook action, a drop-down list of playbooks will appear. Playbooks to which Microsoft Sentinel does not have permissions will show as unavailable ("grayed out"). You can grant Microsoft Sentinel permission to the playbooks' resource groups on the spot by selecting the Manage playbook permissions link. To grant those permissions, you'll need Owner permissions on those resource groups. See the full permissions requirements.
Permissions in a multi-tenant architecture
Therefore, if your Microsoft Sentinel deployment uses a multi-tenant architecture, you can have an automation rule in one tenant run a playbook that lives in a different tenant, but permissions for Sentinel to run the playbooks must be defined in the tenant where the playbooks reside, not in the tenant where the automation rules are defined.
In the specific case of a Managed Security Service Provider (MSSP), where a service provider tenant manages a Microsoft Sentinel workspace in a customer tenant, there are two particular scenarios that warrant your attention:
An automation rule created in the customer tenant is configured to run a playbook located in the service provider tenant.
This approach is normally used to protect intellectual property in the playbook. Nothing special is required for this scenario to work. When defining a playbook action in your automation rule, and you get to the stage where you grant Microsoft Sentinel permissions on the relevant resource group where the playbook is located (using the Manage playbook permissions panel), you'll see the resource groups belonging to the service provider tenant among those you can choose from. See the whole process outlined here.
An automation rule created in the customer workspace (while signed into the service provider tenant) is configured to run a playbook located in the customer tenant.
This configuration is used when there is no need to protect intellectual property. For this scenario to work, permissions to execute the playbook need to be granted to Microsoft Sentinel in both tenants. In the customer tenant, you grant them in the Manage playbook permissions panel, just like in the scenario above. To grant the relevant permissions in the service provider tenant, you need to add an additional Azure Lighthouse delegation that grants access rights to the Azure Security Insights app, with the Microsoft Sentinel Automation Contributor role, on the resource group where the playbook resides.
The scenario looks like this:
See our instructions for setting this up.
Creating and managing automation rules
You can create and manage automation rules from different points in the Microsoft Sentinel experience, depending on your particular need and use case.
Automation rules can be centrally managed in the new Automation blade (which replaces the Playbooks blade), under the Automation rules tab. (You can also now manage playbooks in this blade, under the Playbooks tab.) From there, you can create new automation rules and edit the existing ones. You can also drag automation rules to change the order of execution, and enable or disable them.
In the Automation blade, you see all the rules that are defined on the workspace, along with their status (Enabled/Disabled) and which analytics rules they are applied to.
When you need an automation rule that will apply to many analytics rules, create it directly in the Automation blade. From the top menu, click Create and Add new rule, which opens the Create new automation rule panel. From here you have complete flexibility in configuring the rule: you can apply it to any analytics rules (including future ones) and define the widest range of conditions and actions.
Analytics rule wizard
In the Automated response tab of the analytics rule wizard, you can see, manage, and create automation rules that apply to the particular analytics rule being created or edited in the wizard.
When you click Create and one of the rule types (Scheduled query rule or Microsoft incident creation rule) from the top menu in the Analytics blade, or if you select an existing analytics rule and click Edit, you'll open the rule wizard. When you select the Automated response tab, you will see a section called Incident automation, under which the automation rules that currently apply to this rule will be displayed. You can select an existing automation rule to edit, or click Add new to create a new one.
You'll notice that when you create the automation rule from here, the Create new automation rule panel shows the analytics rule condition as unavailable, because this rule is already set to apply only to the analytics rule you're editing in the wizard. All the other configuration options are still available to you.
You can also create an automation rule from the Incidents blade, in order to respond to a single, recurring incident. This is useful when creating a suppression rule for automatically closing "noisy" incidents. Select an incident from the queue and click Create automation rule from the top menu.
You'll notice that the Create new automation rule panel has populated all the fields with values from the incident. It names the rule the same name as the incident, applies it to the analytics rule that generated the incident, and uses all the available entities in the incident as conditions of the rule. It also suggests a suppression (closing) action by default, and suggests an expiration date for the rule. You can add or remove conditions and actions, and change the expiration date, as you wish.
Auditing automation rule activity
You may be interested in knowing what happened to a given incident, and what a certain automation rule may or may not have done to it. You have a full record of incident chronicles available to you in the SecurityIncident table in the Logs blade. Use the following query to see all your automation rule activity:
SecurityIncident | where ModifiedBy contains "Automation"
In this document, you learned how to use automation rules to manage your Microsoft Sentinel incidents queue and implement some basic incident-handling automation.
- To learn more about advanced automation options, see Automate threat response with playbooks in Microsoft Sentinel.
- For help in implementing automation rules and playbooks, see Tutorial: Use playbooks to automate threat responses in Microsoft Sentinel.
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