AWS GuardDuty threat intel set deleted

Goal

Detect when an attacker is trying to evade defenses by deleting a GuardDuty ThreatIntelSet.

Strategy

This rule lets you monitor this CloudTrail API call to detect if an attacker is deleting a GuardDuty ThreatIntelSet:

Triage and response

  1. Determine if user: {{@userIdentity.arn}} should have made a {{@evt.name}} API call.
  2. If the API call was not made by the user:
  • Rotate user credentials.
  • Determine what other API calls were made by the user.
  • Replace ThreatIntelSets deleted by the user with the aws-cli command create-threat-intel-set or use the AWS Console.
  1. If the API call was made by the user:
  • Determine if the user should be performing this API call and if it was an authorized change.
  • If No, see if other API calls were made by the user and determine if they warrant further investigation.