Detection: Previously Seen AWS Cross Account Activity - Update

REMOVED DETECTION

This detection has been removed from the Splunk Threat Research content library and is no longer maintained or supported.

Reason: All detection(s) which leverage this baseline have been deprecated. As such, this baseline has been deprecated as well.

Removed in version: 5.4.0

If you have any questions or concerns, please reach out to us at research@splunk.com.

Updated Date: 2026-05-13 ID: dd6fb3a9-4906-48cb-8626-c88a25a056c3 Author: Rico Valdez, Splunk Type: Baseline Product: Splunk Enterprise Security

Description

This search looks for AssumeRole events where the requesting account differs from the requested account, then writes these relationships to a lookup file.

Search

1
2| tstats earliest(_time) as firstTime latest(_time) as lastTime from datamodel=Authentication where Authentication.signature=AssumeRole by Authentication.vendor_account Authentication.user Authentication.src Authentication.user_role 
3| `drop_dm_object_name(Authentication)` 
4| rex field=user_role "arn:aws:sts:*:(?<dest_account>.*):" 
5| where vendor_account != dest_account 
6| rename vendor_account as requestingAccountId dest_account as requestedAccountId 
7| inputlookup append=t previously_seen_aws_cross_account_activity 
8| stats min(firstTime) as firstTime max(lastTime) as lastTime by requestingAccountId requestedAccountId 
9| outputlookup previously_seen_aws_cross_account_activity

Data Source

No data sources specified for this detection.

Macros Used

Name	Value
drop_dm_object_name	``

Annotations

- MITRE ATT&CK

+ Kill Chain Phases

+ NIST

+ CIS

- Threat Actors

ID	Technique	Tactic

Default Configuration

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

Setting	Value
Disabled	true
Cron Schedule	`N/A`
Earliest Time	`N/A`
Latest Time	`N/A`
Schedule Window	`N/A`
Creates Finding (Notable)	No
Creates Intermediate Finding (Risk Event)	No

Implementation

You must install and configure the Splunk Add-on for AWS (version 5.1.0 or later) and Enterprise Security 6.2, which contains the required updates to the Authentication data model for cloud use cases. Validate the user name entries in previously_seen_aws_cross_account_activity kvstore

Known False Positives

none

Associated Analytic Story

Suspicious Cloud Authentication Activities

Detection Testing

Test Type	Status	Dataset	Source	Sourcetype
Validation	Not Applicable	N/A	N/A	N/A
Unit	Not Applicable	N/A	`N/A`	`N/A`
Integration	Not Applicable	N/A	`N/A`	`N/A`

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