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Description

The following query uses IAM events to track the success of a group being deleted on AWS. This is typically not indicative of malicious behavior, but a precurser to additional events thay may unfold. Review parallel IAM events - recently added users, new groups and so forth. Inversely, review failed attempts in a similar manner.

  • Type: Hunting

  • Product: Splunk Enterprise, Splunk Enterprise Security, Splunk Cloud

  • Last Updated: 2021-03-31
  • Author: Michael Haag, Splunk
  • ID: e776d06c-9267-11eb-819b-acde48001122

Annotations

ATT&CK

ATT&CK

ID Technique Tactic
T1069.003 Cloud Groups Discovery
T1098 Account Manipulation Persistence
T1069 Permission Groups Discovery Discovery
Kill Chain Phase
  • Exploitation
  • Installation
NIST
  • DE.AE
CIS20
  • CIS 10
CVE 


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`cloudtrail` eventSource=iam.amazonaws.com eventName=DeleteGroup errorCode=success (userAgent!=*.amazonaws.com) 
| stats count min(_time) as firstTime max(_time) as lastTime values(requestParameters.groupName) as group_deleted by src eventName eventSource errorCode user_agent awsRegion userIdentity.principalId user_arn 
| `security_content_ctime(firstTime)` 
| `security_content_ctime(lastTime)` 
| `aws_iam_successful_group_deletion_filter`

Macros

The SPL above uses the following Macros:

:information_source: aws_iam_successful_group_deletion_filter is a empty macro by default. It allows the user to filter out any results (false positives) without editing the SPL.

Required fields

List of fields required to use this analytic.

  • _time
  • eventName
  • userAgent
  • errorCode
  • requestParameters.groupName

How To Implement

The Splunk AWS Add-on and Splunk App for AWS is required to utilize this data. The search requires AWS Cloudtrail logs.

Known False Positives

This detection will require tuning to provide high fidelity detection capabilties. Tune based on src addresses (corporate offices, VPN terminations) or by groups of users. Not every user with AWS access should have permission to delete groups (least privilege).

Associated Analytic Story

RBA

Risk Score Impact Confidence Message
5.0 10 50 User $user_arn$ has sucessfully deleted mulitple groups $group_deleted$ from $src$

:information_source: The Risk Score is calculated by the following formula: Risk Score = (Impact * Confidence/100). Initial Confidence and Impact is set by the analytic author.

Reference

Test Dataset

Replay any dataset to Splunk Enterprise by using our replay.py tool or the UI. Alternatively you can replay a dataset into a Splunk Attack Range

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