Detection: AWS Cloud Provisioning From Previously Unseen City

DEPRECATED DETECTION

This detection has been marked as deprecated by the Splunk Threat Research team. This means that it will no longer be maintained or supported. If you have any questions or concerns, please reach out to us at research@splunk.com.

Updated Date: 2024-08-16 ID: 344a1778-0b25-490c-adb1-de8beddf59cd Author: David Dorsey, Splunk Type: Anomaly Product: Splunk Enterprise Security

Description

This search looks for AWS provisioning activities from previously unseen cities. Provisioning activities are defined broadly as any event that begins with "Run" or "Create." This search is deprecated and have been translated to use the latest Change Datamodel.

Search

 1`cloudtrail` (eventName=Run* OR eventName=Create*) 
 2| iplocation sourceIPAddress 
 3| search City=* [search `cloudtrail` (eventName=Run* OR eventName=Create*) 
 4| iplocation sourceIPAddress 
 5| search City=* 
 6| stats earliest(_time) as firstTime, latest(_time) as lastTime by sourceIPAddress, City, Region, Country 
 7| inputlookup append=t previously_seen_provisioning_activity_src.csv 
 8| stats min(firstTime) as firstTime max(lastTime) as lastTime by sourceIPAddress, City, Region, Country 
 9| outputlookup previously_seen_provisioning_activity_src.csv 
10| stats min(firstTime) as firstTime max(lastTime) as lastTime by City 
11| eval newCity=if(firstTime >= relative_time(now(), "-70m@m"), 1, 0) 
12| where newCity=1 
13| table City] 
14| spath output=user userIdentity.arn 
15| rename sourceIPAddress as src_ip 
16| table _time, user, src_ip, City, eventName, errorCode 
17| `aws_cloud_provisioning_from_previously_unseen_city_filter`

Data Source

Name	Platform	Sourcetype	Source	Supported App
N/A	N/A	N/A	N/A	N/A

Macros Used

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

aws_cloud_provisioning_from_previously_unseen_city_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
T1535	Unused/Unsupported Cloud Regions	Defense Evasion

KillChainPhase.EXPLOITAITON

NistCategory.DE_AE

Cis18Value.CIS_10

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	True

This configuration file applies to all detections of type anomaly. These detections will use Risk Based Alerting.

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. This search works best when you run the "Previously Seen AWS Provisioning Activity Sources" support search once to create a history of previously seen locations that have provisioned AWS resources.

Known False Positives

This is a strictly behavioral search, so we define "false positive" slightly differently. Every time this fires, it will accurately reflect the first occurrence in the time period you're searching within, plus what is stored in the cache feature. But while there are really no "false positives" in a traditional sense, there is definitely lots of noise. This search will fire any time a new city is seen in the GeoIP database for any kind of provisioning activity. If you typically do all provisioning from tools inside of your city, there should be few false positives. If you are located in countries where the free version of MaxMind GeoIP that ships by default with Splunk has weak resolution (particularly small countries in less economically powerful regions), this may be much less valuable to you.

Associated Analytic Story

AWS Suspicious Provisioning Activities

Risk Based Analytics (RBA)

Risk Message	Risk Score	Impact	Confidence
tbd	25	50	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.

Detection Testing

Test Type	Status	Dataset	Source	Sourcetype
Validation	Not Applicable	N/A	N/A	N/A
Unit	❌ Failing	N/A	`N/A`	`N/A`
Integration	❌ Failing	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: 2