Anomalous number of assumed roles from user


Detect when a user has attempted to assume an anomalous number of unique roles.


This rule sets a baseline for user activity for the AssumeRole API call, and enables detection of potentially anomalous activity.

An attacker may attempt this for the following reasons:

  • To identify which roles the user account has access to.
  • To identify what AWS services are being used internally.
  • To identify third party integrations and internal software.

Triage and response

  1. Investigate activity for the following ARN {{@userIdentity.arn}} using {{@userIdentity.session_name}}.
  2. Review any other security signals for {{@userIdentity.arn}}.
  3. If the activity is deemed malicious:
    • Rotate user credentials.
    • Determine what other API calls were made by the user.
    • Begin your organization’s incident response process and investigate.