Detection: AWS IAM Successful Group Deletion

Updated Date: 2024-05-29 ID: e776d06c-9267-11eb-819b-acde48001122 Author: Michael Haag, Splunk Type: Hunting Product: Splunk Enterprise Security

Description

The following analytic identifies the successful deletion of an IAM group in AWS. It leverages CloudTrail logs to detect DeleteGroup events with a success status. This activity is significant as it could indicate potential changes in user permissions or access controls, which may be a precursor to further unauthorized actions. If confirmed malicious, an attacker could disrupt access management, potentially leading to privilege escalation or unauthorized access to sensitive resources. Analysts should review related IAM events, such as recent user additions or new group creations, to assess the broader context.

Search

1`cloudtrail` eventSource=iam.amazonaws.com eventName=DeleteGroup errorCode=success (userAgent!=*.amazonaws.com) 
2| 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 
3| `security_content_ctime(firstTime)` 
4| `security_content_ctime(lastTime)` 
5| `aws_iam_successful_group_deletion_filter`

Data Source

Name	Platform	Sourcetype	Source	Supported App
AWS CloudTrail DeleteGroup	AWS	`'aws:cloudtrail'`	`'aws_cloudtrail'`	N/A

Macros Used

Name	Value
cloudtrail	`sourcetype=aws:cloudtrail`
aws_iam_successful_group_deletion_filter	`search *`

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

Annotations

- MITRE ATT&CK

+ Kill Chain Phases

+ NIST

+ CIS

- Threat Actors

ID	Technique	Tactic
T1069.003	Cloud Groups	Discovery
T1098	Account Manipulation	Persistence
T1069	Permission Groups Discovery	Privilege Escalation

KillChainPhase.EXPLOITAITON

KillChainPhase.INSTALLATION

NistCategory.DE_AE

Cis18Value.CIS_10

APT3

APT41

APT5

Dragonfly

FIN13

HAFNIUM

Kimsuky

Lazarus Group

Magic Hound

APT3

APT41

FIN13

TA505

Default Configuration

This detection is configured by default in Splunk Enterprise Security to run with the following settings:

Setting	Value
Disabled	true
Cron Schedule	`0 * * * *`
Earliest Time	`-70m@m`
Latest Time	`-10m@m`
Schedule Window	`auto`
Creates Risk Event	False

This configuration file applies to all detections of type hunting.

Implementation

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

AWS IAM Privilege Escalation

Risk Based Analytics (RBA)

Risk Message	Risk Score	Impact	Confidence
User $user_arn$ has sucessfully deleted mulitple groups $group_deleted$ from $src$	5	10	50

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

References

Detection Testing

Test Type	Status	Dataset	Source	Sourcetype
Validation	✅ Passing	N/A	N/A	N/A
Unit	✅ Passing	Dataset	`aws_cloudtrail`	`aws:cloudtrail`
Integration	✅ Passing	Dataset	`aws_cloudtrail`	`aws:cloudtrail`

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

Source: GitHub | Version: 2