Control: 5.2.2 Ensure that Activity Log Alert exists for Delete Policy Assignment

Description

Create an activity log alert for the Delete Policy Assignment event.

Monitoring for delete policy assignment events gives insight into changes done in "azure policy - assignments" and can reduce the time it takes to detect unsolicited changes.

Remediation

From Azure Portal

Navigate to the Monitor blade
Click on Alerts
Click on Create
Click on Alert rule
Under the Scope tab, click Select scope
In the Select a resource window, select the appropriate filters:
- Filter by subscription: < choose the subscription alerts are needed for >
- Filter by resource location: Policy assignment (policyAssignments)
- Filter by location: All
- Click on the subscription name or resource group to apply the Log Alert Rule to
Verify that the selection preview shows:
- All Policy assignment (policyAssignments)
- < Resource Name > - The subscription, group, or resource you selected
Click Done
Under the Condition tab, click Add Condition (the Select a signal window may automatically open without clicking)
In the Select a signal window, under the "Signal Name" heading, click Delete policy assignment (Microsoft.Authorization/policyAssignments)
Under the Actions tab, choose appropriately:
- Select action groups - If you have an existing action group to notify the necessary personnel.
- Create action group - If you do not have an existing action group or want to create a new one.
Under the Details tab, fill in:
- Resource group - Select the resource group you want the alert rule to reside in.
- Alert rule name - Give your alert a recognizable and standardized name.
- Alert rule description - (Optional)
Click Review + create then verify the summary details
Click Create

From Azure CLI

[Azure CLI has been temporarily removed from the Activity Log Alerts section in version 1.5 and will be added back in the next release]

Default Value

By default, no monitoring alerts are created.

Usage

Run the control in your terminal:

powerpipe control run azure_compliance.control.cis_v150_5_2_2

Snapshot and share results via Turbot Pipes:

powerpipe login
powerpipe control run azure_compliance.control.cis_v150_5_2_2 --share

SQL

This control uses a named query:

with alert_rule as (
  select
    alert.id as alert_id,
    alert.name as alert_name,
    alert.enabled,
    alert.location,
    alert.subscription_id
  from
    azure_log_alert as alert,
    jsonb_array_elements_text(scopes) as sc
  where
    alert.location = 'global'
    and alert.enabled
    and sc = '/subscriptions/' || alert.subscription_id
    and alert.condition -> 'allOf' @> '[{"equals":"Administrative","field":"category"}]'
    and alert.condition -> 'allOf' @> '[{"field": "operationName", "equals": "Microsoft.Authorization/policyAssignments/delete"}]'
  limit 1
)
select
  sub.subscription_id as resource,
  case
    when count(a.subscription_id) > 0 then 'ok'
    else 'alarm'
  end as status,
  case
    when count(a.subscription_id) > 0 then 'Activity log alert exists for delete policy assignment event.'
    else 'Activity log alert does not exists for delete policy assignment event.'
  end as reason
  
  , sub.display_name as subscription
from
  azure_subscription sub
  left join alert_rule a on sub.subscription_id = a.subscription_id
group by
  sub._ctx,
  sub.subscription_id,
  sub.display_name;