Detection: AWS CreateAccessKey

Updated Date: 2024-05-12 ID: 2a9b80d3-6340-4345-11ad-212bf3d0d111 Author: Bhavin Patel, 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`cloudtrail` eventName = CreateAccessKey userAgent !=console.amazonaws.com errorCode = success 
2| eval match=if(match(userIdentity.userName,requestParameters.userName),1,0) 
3| search match=0 
4| stats count min(_time) as firstTime max(_time) as lastTime by requestParameters.userName src eventName eventSource aws_account_id errorCode userAgent eventID awsRegion userIdentity.principalId user_arn 
5| `security_content_ctime(firstTime)` 
6| `security_content_ctime(lastTime)` 
7|`aws_createaccesskey_filter`

Data Source

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

Macros Used

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

aws_createaccesskey_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

KillChainPhase.INSTALLATION

NistCategory.DE_AE

Cis18Value.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

You must install splunk AWS add on and Splunk App for AWS. This search works with AWS CloudTrail logs.

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

Risk Based Analytics (RBA)

Risk Message	Risk Score	Impact	Confidence
User $user_arn$ is attempting to create access keys for $requestParameters.userName$ from this IP $src$	63	70	90

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: 4