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Description

This search looks for AWS CloudTrail events wherein a console login event by a user was recorded within the last hour, then compares the event to a lookup file of previously seen users (by ARN values) who have logged into the console. The alert is fired if the user has logged into the console for the first time within the last hour

  • Type: Hunting
  • Product: Splunk Security Analytics for AWS, Splunk Enterprise, Splunk Enterprise Security, Splunk Cloud
  • Datamodel: Authentication
  • Last Updated: 2020-05-28
  • Author: Rico Valdez, Splunk
  • ID: bc91a8cd-35e7-4bb2-6140-e756cc46fd71

| tstats earliest(_time) as firstTime latest(_time) as lastTime from datamodel=Authentication where Authentication.signature=ConsoleLogin by Authentication.user 
| `drop_dm_object_name(Authentication)` 
| inputlookup append=t previously_seen_users_console_logins 
| stats min(firstTime) as firstTime max(lastTime) as lastTime by user 
| eval userStatus=if(firstTime >=relative_time(now(),"-24h@h"), "First Time Logging into AWS Console", "Previously Seen User") 
|where userStatus="First Time Logging into AWS Console" 
|  `security_content_ctime(firstTime)` 
| `security_content_ctime(lastTime)`
| `detect_aws_console_login_by_new_user_filter`

Associated Analytic Story

How To Implement

You must install and configure the Splunk Add-on for AWS (version 5.1.0 or later) and Enterprise Security 6.2, which contains the required updates to the Authentication data model for cloud use cases. Run the Previously Seen Users in AWS CloudTrail - Initial support search only once to create a baseline of previously seen IAM users within the last 30 days. Run Previously Seen Users in AWS CloudTrail - Update hourly (or more frequently depending on how often you run the detection searches) to refresh the baselines.

Required field

  • _time
  • Authentication.signature
  • Authentication.user

Kill Chain Phase

  • Actions on Objectives

Known False Positives

When a legitimate new user logins for the first time, this activity will be detected. Check how old the account is and verify that the user activity is legitimate.

RBA

Risk Score Impact Confidence Message
30.0 50 60 User $user$ is logging into the AWS console 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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