THIS IS A DEPRECATED DETECTION
This detection has been marked deprecated by the Splunk Threat Research team. This means that it will no longer be maintained or supported.
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.
- Type: Hunting
Product: Splunk Enterprise, Splunk Enterprise Security, Splunk Cloud
- Last Updated: 2020-07-21
- Author: Bhavin Patel, Splunk
- ID: ada0f478-84a8-4641-a3f1-d82362d4bd55
Kill Chain Phase
- Actions on Objectives
- CIS 16
1 2 3 4 5 6 7 8 9 10 11 12 13 `cloudtrail` errorCode=success | rename userName as identity | search NOT [ | inputlookup identity_lookup_expanded | fields identity] | search NOT [ | inputlookup aws_service_accounts | fields identity] | rename identity as user | stats count min(_time) as firstTime max(_time) as lastTime values(eventName) as eventName by user | `security_content_ctime(firstTime)` | `security_content_ctime(lastTime)` | `detect_aws_api_activities_from_unapproved_accounts_filter`
The SPL above uses the following Macros:
detect_aws_api_activities_from_unapproved_accounts_filter is a empty macro by default. It allows the user to filter out any results (false positives) without editing the SPL.
The SPL above uses the following Lookups:
List of fields required to use this analytic.
How To Implement
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 (
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):\n1. 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:
Known False Positives
It's likely that you'll find activity detected by users/service accounts that are not listed in the
identity_lookup_expandedor ` aws_service_accounts.csv
file. If the user is a legitimate service account, update theaws_service_accounts.csv` table with that entry.
Associated Analytic Story
The Risk Score is calculated by the following formula: Risk Score = (Impact * Confidence/100). Initial Confidence and Impact is set by the analytic author.
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