Detection: ASL AWS Create Access Key

Updated Date: 2024-12-12 ID: 81a9f2fe-1697-473c-af1d-086b0d8b63c8 Author: Patrick Bareiss, Splunk Type: Hunting Product: Splunk Enterprise Security

Description

The following analytic identifies the creation of AWS IAM access keys by a user for another user, which can indicate privilege escalation. It leverages AWS CloudTrail logs to detect instances where the user creating the access key is different from the user for whom the key is created. This activity is significant because unauthorized access key creation can allow attackers to establish persistence or exfiltrate data via AWS APIs. If confirmed malicious, this could lead to unauthorized access to AWS services, data exfiltration, and long-term persistence in the environment.

Search

1`amazon_security_lake` api.operation=CreateAccessKey 
2| fillnull 
3| stats count min(_time) as firstTime max(_time) as lastTime by api.operation actor.user.uid actor.user.account.uid http_request.user_agent src_endpoint.ip cloud.region 
4| rename actor.user.uid as user, src_endpoint.ip as src_ip, cloud.region as region, http_request.user_agent as user_agent 
5| `security_content_ctime(firstTime)` 
6| `security_content_ctime(lastTime)` 
7|`asl_aws_create_access_key_filter`

Data Source

Name	Platform	Sourcetype	Source
ASL AWS CloudTrail	AWS	`'aws:asl'`	`'aws_asl'`

Macros Used

Name	Value
amazon_security_lake	`sourcetype=aws:asl`
asl_aws_create_access_key_filter	`search *`

asl_aws_create_access_key_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
T1136.003	Cloud Account	Persistence
T1136	Create Account	Persistence

Installation

DE.AE

CIS 13

APT29

LAPSUS$

Indrik Spider

Scattered Spider

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 detection is based on Amazon Security Lake events from Amazon Web Services (AWS), which is a centralized data lake that provides security-related data from AWS services. To use this detection, you must ingest CloudTrail logs from Amazon Security Lake into Splunk. To run this search, ensure that you ingest events using the latest version of Splunk Add-on for Amazon Web Services (https://splunkbase.splunk.com/app/1876) or the Federated Analytics App.

Known False Positives

While this search has no known false positives, it is possible that an AWS admin has legitimately created keys for another user.

Associated Analytic Story

AWS IAM Privilege Escalation

References

Detection Testing

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

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: 1