:warning: THIS IS A EXPERIMENTAL DETECTION

This detection has been marked experimental by the Splunk Threat Research team. This means we have not been able to test, simulate, or build datasets for this detection. Use at your own risk. This analytic is NOT supported.

Try in Splunk Security Cloud

Description

This search looks for AWS CloudTrail events and analyse the amount of eventNames which starts with Describe by a single user. This indicates that this user scans the configuration of your AWS cloud environment.

  • Type: Anomaly

  • Product: Splunk Enterprise, Splunk Enterprise Security, Splunk Cloud

  • Last Updated: 2023-06-01
  • Author: Patrick Bareiss, Splunk
  • ID: ff2bfdbc-65b7-4434-8f08-d55761d1d446

Annotations

ATT&CK

ATT&CK

ID Technique Tactic
T1526 Cloud Service Discovery Discovery
Kill Chain Phase
  • Exploitation
NIST
  • DE.AE
CIS20
  • CIS 13
CVE 


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`amazon_security_lake` api.operation=Describe* OR api.operation=List* OR api.operation=Get* 
| stats dc(api.operation) as dc_api_operations min(_time) as firstTime max(_time) as lastTime values(http_request.user_agent) as http_request.user_agent values(src_endpoint.ip) as src_endpoint.ip values(cloud.region) as cloud.region values(identity.user.account_uid) as identity.user.account_uid by identity.user.name 
| where dc_api_operations > 50 
| `security_content_ctime(firstTime)` 
| `security_content_ctime(lastTime)`
|`asl_aws_excessive_security_scanning_filter`

Macros

The SPL above uses the following Macros:

:information_source: asl_aws_excessive_security_scanning_filter is a empty macro by default. It allows the user to filter out any results (false positives) without editing the SPL.

Required fields

List of fields required to use this analytic.

  • api.operation
  • identity.user.account_uid
  • identity.user.name
  • http_request.user_agent
  • src_endpoint.ip

How To Implement

You must install Splunk Add-On for AWS Version v7.0.0 (https://splunkbase.splunk.com/app/1876) that includes includes a merge of all the capabilities of the Splunk Add-on for Amazon Security Lake. This search works with Amazon Security Lake logs which are parsed in the Open Cybersecurity Schema Framework (OCSF)format.

Known False Positives

While this search has no known false positives.

Associated Analytic Story

RBA

Risk Score Impact Confidence Message
18.0 30 60 user $identity.user.name$ has excessive number of api calls.

:information_source: The Risk Score is calculated by the following formula: Risk Score = (Impact * Confidence/100). Initial Confidence and Impact is set by the analytic author.

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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