ID | Technique | Tactic |
---|---|---|
T1535 | Unused/Unsupported Cloud Regions | Defense Evasion |
Detection: EC2 Instance Started In Previously Unseen Region
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.
Description
This search looks for AWS CloudTrail events where an instance is started in a particular region in the last one hour and then compares it to a lookup file of previously seen regions where an instance was started
Search
1`cloudtrail` earliest=-1h StartInstances
2| stats earliest(_time) as earliest latest(_time) as latest by awsRegion
3| inputlookup append=t previously_seen_aws_regions.csv
4| stats min(earliest) as earliest max(latest) as latest by awsRegion
5| outputlookup previously_seen_aws_regions.csv
6| eval regionStatus=if(earliest >= relative_time(now(),"-1d@d"), "Instance Started in a New Region","Previously Seen Region")
7| `security_content_ctime(earliest)`
8| `security_content_ctime(latest)`
9| where regionStatus="Instance Started in a New Region"
10| `ec2_instance_started_in_previously_unseen_region_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 |
ec2_instance_started_in_previously_unseen_region_filter | search * |
ec2_instance_started_in_previously_unseen_region_filter
is an empty macro by default. It allows the user to filter out any results (false positives) without editing the SPL.
Annotations
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 |
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. Run the "Previously seen AWS Regions" support search only once to create of baseline of previously seen regions. This search is deprecated and have been translated to use the latest Change Datamodel.
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.
Associated Analytic Story
Risk Based Analytics (RBA)
Risk Message | Risk Score | Impact | Confidence |
---|---|---|---|
tbd | 25 | 50 | 50 |
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