Detection: ASL AWS IAM Successful Group Deletion

Updated Date: 2024-10-22 ID: 1bbe54f1-93d7-4764-8a01-ddaa12ece7ac Author: Patrick Bareiss, Splunk Type: Hunting Product: Splunk Enterprise Security

Description

The following analytic detects the successful deletion of a group within AWS IAM, leveraging CloudTrail IAM events. This action, while not inherently malicious, can serve as a precursor to more sinister activities, such as unauthorized access or privilege escalation attempts. By monitoring for such deletions, the analytic aids in identifying potential preparatory steps towards an attack, allowing for early detection and mitigation. The identification of this behavior is crucial for a SOC to prevent the potential impact of an attack, which could include unauthorized access to sensitive resources or disruption of AWS environment operations.

Search

1`amazon_security_lake` api.operation=DeleteGroup status=Success 
2| fillnull 
3| stats count min(_time) as firstTime max(_time) as lastTime by api.operation actor.user.account_uid actor.user.name actor.user.uid http_request.user_agent src_endpoint.ip cloud.region 
4| rename actor.user.name as user, src_endpoint.ip as src_ip, cloud.region as region, http_request.user_agent as user_agent, actor.user.account_uid as aws_account_id 
5| `security_content_ctime(firstTime)` 
6| `security_content_ctime(lastTime)` 
7| `asl_aws_iam_successful_group_deletion_filter`

Data Source

No data sources specified for this detection.

Macros Used

Name	Value
amazon_security_lake	`sourcetype=aws:cloudtrail:lake`
asl_aws_iam_successful_group_deletion_filter	`search *`

asl_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

HAFNIUM

Lazarus Group

APT3

APT41

FIN13

TA505

Volt Typhoon

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

You must install the Data Lake Federated Analytics App and ingest the logs into Splunk.

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 $user$ has sucessfully deleted a user group from $src_ip$	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_asl`	`aws:cloudtrail:lake`
Integration	✅ Passing	Dataset	`aws_asl`	`aws:cloudtrail:lake`

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: 4