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Description

This search looks at cloud-infrastructure events where an instance is created in any region within the last hour and then compares it to a lookup file of previously seen regions where instances have been created.

  • Type: Anomaly
  • Product: Splunk Security Analytics for AWS, Splunk Enterprise, Splunk Enterprise Security, Splunk Cloud
  • Datamodel: Change
  • Last Updated: 2020-09-02
  • Author: David Dorsey, Splunk
  • ID: fa4089e2-50e3-40f7-8469-d2cc1564ca59

ATT&CK

ID Technique Tactic
T1535 Unused/Unsupported Cloud Regions Defense Evasion 

| tstats earliest(_time) as firstTime latest(_time) as lastTime values(All_Changes.object_id) as dest, count from datamodel=Change where All_Changes.action=created by All_Changes.vendor_region, All_Changes.user 
| `drop_dm_object_name("All_Changes")` 
| lookup previously_seen_cloud_regions vendor_region as vendor_region OUTPUTNEW firstTimeSeen, enough_data 
| eventstats max(enough_data) as enough_data 
| where enough_data=1 
| eval firstTimeSeenRegion=min(firstTimeSeen) 
| where isnull(firstTimeSeenRegion) OR firstTimeSeenRegion > relative_time(now(), "-24h@h") 
| table firstTime, user, dest, count , vendor_region 
| `security_content_ctime(firstTime)` 
| `cloud_compute_instance_created_in_previously_unused_region_filter`

Associated Analytic Story

How To Implement

You must be ingesting your cloud infrastructure logs from your cloud provider. You should run the baseline search Previously Seen Cloud Regions - Initial to build the initial table of images observed and times. You must also enable the second baseline search Previously Seen Cloud Regions - Update to keep this table up to date and to age out old data. You can also provide additional filtering for this search by customizing the cloud_compute_instance_created_in_previously_unused_region_filter macro.

Required field

  • _time
  • All_Changes.object_id
  • All_Changes.action
  • All_Changes.vendor_region
  • All_Changes.user

Kill Chain Phase

  • Actions on Objectives

Known False Positives

It's possible that a user has unknowingly started an instance in a new region. Please verify that this activity is legitimate.

RBA

Risk Score Impact Confidence Message
42.0 70 60 User $user$ is creating an instance $dest$ in a new region for the first time

Reference

Test Dataset

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

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