Description
Ensure an Events Service rule in the root compartment watches for IAM user changes and has an action that sends a notification to a monitored topic. The rule should match all of the related event types, so the security team is alerted as soon as these changes happen.
Rationale
Creating a new user or changing an existing user's state or capabilities can give an attacker a lasting foothold in the tenancy. Alerting on user changes lets the security team confirm that every new account and every change to an account is expected and approved.
Impact
The security team is alerted when a user is created, changed, or deleted
Speeds up detection of unauthorized or accidental changes
Alert volume depends on how often these changes happen
Default Value
By default, no event rules or notification topics are configured.
Pre-Requisites
Permission to manage cloudevents-rules and ons-topics in the root compartment
A notification topic with at least one confirmed subscription (for example, the security team's email address)
Test Plan
Sign in to the OCI Console at https://cloud.oracle.com.
Open the navigation menu, select Observability & Management, and under Events Service select Rules. In the Compartment filter, select the root compartment (tenancy).
Look for an enabled rule whose conditions match the Identity service and these event types: User – Create, User – Delete, User – Update, User Capabilities – Update, and User State – Update.
Open the rule and verify that its Actions include a Notifications action pointing to a topic with an active subscription.
If no such rule exists, or it has no notification action, follow the implementation steps.
Implementation Steps
Sign in to the OCI Console at https://cloud.oracle.com.
If you do not have a topic, open Developer Services > Application Integration > Notifications, select Create topic, then create a subscription (for example, Email) and confirm it.
Open the navigation menu, select Observability & Management, and under Events Service select Rules. In the Compartment filter, select the root compartment (tenancy).
Select Create rule and enter a name, for example notify-on-user-changes.
Under Rule conditions, choose Event type, select Service name Identity, and select the event types: User – Create, User – Delete, User – Update, User Capabilities – Update, and User State – Update.
Under Actions, choose Action type Notifications, and select the compartment and topic.
Select Create rule.
Backout Plan
Sign in to the OCI Console at https://cloud.oracle.com.
Open the navigation menu, select Observability & Management, and under Events Service select Rules. In the Compartment filter, select the root compartment (tenancy).
Select the rule and select Disable, or delete the rule.
Reference
https://docs.oracle.com/en-us/iaas/Content/Events/Task/managingrules.htm
https://docs.oracle.com/en-us/iaas/Content/Security/Reference/iam_security.htm