Detection: Detect AWS API Activities From Unapproved Accounts

Description

This search looks for successful AWS CloudTrail activity by user accounts that are not listed in the identity table or aws_service_accounts.csv. It returns event names and count, as well as the first and last time a specific user or service is detected, grouped by users. Deprecated because managing this list can be quite hard.

Search

 1`cloudtrail` errorCode=success 
 2| rename userName as identity 
 3| search NOT [
 4| inputlookup identity_lookup_expanded 
 5| fields identity] 
 6| search NOT [
 7| inputlookup aws_service_accounts 
 8| fields identity] 
 9| rename identity as user 
10| stats count min(_time) as firstTime max(_time) as lastTime values(eventName) as eventName by user 
11| `security_content_ctime(firstTime)` 
12| `security_content_ctime(lastTime)` 
13| `detect_aws_api_activities_from_unapproved_accounts_filter`

Data Source

Macros Used

Annotations

Default Configuration

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

Implementation

You must install the AWS App for Splunk (version 5.1.0 or later) and Splunk Add-on for AWS (version 4.4.0 or later), then configure your AWS CloudTrail inputs. You must also populate the identity_lookup_expanded lookup shipped with the Asset and Identity framework to be able to look up users in your identity table in Enterprise Security (ES). Leverage the support search called "Create a list of approved AWS service accounts": run it once every 30 days to create and validate a list of service accounts. This search produces fields (eventName,firstTime,lastTime) that are not yet supported by ES Incident Review and therefore cannot be viewed when a notable event is raised. These fields contribute additional context to the notable. To see the additional metadata, add the following fields, if not already present, to Incident Review - Event Attributes (Configure > Incident Management > Incident Review Settings > Add New Entry):

• Label: AWS Event Name, Field: eventName
• Label: First Time, Field: firstTime
• Label: Last Time, Field: lastTime Detailed documentation on how to create a new field within Incident Review may be found here: https://docs.splunk.com/Documentation/ES/5.3.0/Admin/Customizenotables#Add_a_field_to_the_notable_event_details

Known False Positives

It's likely that you'll find activity detected by users/service accounts that are not listed in the identity_lookup_expanded or aws_service_accounts.csv file. If the user is a legitimate service account, update the aws_service_accounts.csv table with that entry.

Associated Analytic Story

• AWS User Monitoring

Risk Based Analytics (RBA)

Detection Testing

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: 3