Privilege Escalation: Impersonation Role Granted for Dormant Service Account

This document describes a threat finding type in Security Command Center. Threat findings are generated by threat detectors when they detect a potential threat in your cloud resources. For a full list of available threat findings, see Threat findings index.

Finding description

An impersonation role was granted to a principal that allows that principal to impersonate a dormant user-managed service account. In this finding, the dormant service account is the affected resource, and a service account is considered dormant if it has been inactive for more than 180 days.

To respond to this finding, do the following:

Step 1: Review finding details

  1. Open the Privilege Escalation: Impersonation Role Granted for Dormant Service Account finding, as directed in Reviewing findings.

  2. In the finding details, on the Summary tab, note the values of following fields.

    Under What was detected:

    • Principal email: the user who conducted the granting action
    • Offending access grants.Principal name: the principal who was granted the impersonation role

    Under Affected resource:

    • Resource display name: the dormant service account as a resource
    • Project full name: the project where that dormant service account resides

Step 2: Research attack and response methods

  1. Use service account tools, like Activity Analyzer, to investigate the activity of the dormant service account.
  2. Contact the owner of the Principal email field. Confirm whether the legitimate owner conducted the action.

Step 3: Check logs

  1. On the Summary tab of the finding details panel, under the Related links click the Cloud Logging URI link to open the Logs Explorer.

Step 4: Implement your response

The following response plan might be appropriate for this finding, but might also impact operations. Carefully evaluate the information you gather in your investigation to determine the best way to resolve findings.

  • Contact the owner of the project where the action was taken.
  • Remove the access of the owner of the Principal email if it is compromised.
  • Remove the newly granted impersonation role from the target member.
  • Consider deleting the potentially compromised service account and rotate and delete all service account access keys for the potentially compromised project. After deletion, applications that use the service account for authentication lose access. Before proceeding, your security team should identify all impacted applications and work with application owners to ensure business continuity.
  • Work with your security team to identify unfamiliar resources, including Compute Engine instances, snapshots, service accounts, and IAM users. Delete resources not created with authorized accounts.
  • Respond to any notifications from Cloud Customer Care.
  • To limit who can create service accounts, use the Organization Policy Service.
  • To identify and fix overly permissive roles, use IAM recommender.

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